Liquid chemical and method for producing liquid chemical

ABSTRACT

An object of the present invention is to provide a liquid chemical exhibiting excellent defect inhibitive performance even in a case of being applied to a resist process by EUV exposure. Another object thereof is to provide a method for producing a liquid chemical. The liquid chemical of the present invention includes an organic solvent; Fe nanoparticles containing a Fe atom and having a particle size of 0.5 to 17 nm; and Pb nanoparticles containing a Pb atom and having a particle size of 0.5 to 17 nm, in which a ratio of the number of the Fe nanoparticles contained to the number of the Pb nanoparticles contained is 1.0 to 1.0×104, based on the number of the particles per unit volume of the liquid chemical.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No.PCT/JP2019/000340 filed on Jan. 9, 2019, which claims priority under 35U.S.C. § 119(a) to Japanese Patent Application No. 2018-003582 filed onJan. 12, 2018. Each of the above applications is hereby expresslyincorporated by reference, in its entirety, into the presentapplication.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a liquid chemical and a method forproducing a liquid chemical.

2. Description of the Related Art

In a case of manufacturing a semiconductor device by a wiring formingstep including photolithography, a liquid chemical containing waterand/or an organic solvent is used as a pre-wetting solution, a resistsolution (a resist composition), a developer, a rinsing solution, apeeling solution, a slurry for chemical mechanical polishing (CMP), anda cleaning liquid or the like after CMP, or as a dilute solutiontherefor.

In recent years, miniaturization of patterns has been progressing inaccordance with progress of photolithography technology. As a method ofminiaturizing patterns, a method of shortening a wavelength of anexposure light source is used. Attempts have been made to form patternsusing extreme ultraviolet (EUV) having a shorter wavelength as anexposure light source instead of ultraviolet rays, a KrF excimer laser,an ArF excimer laser, and the like which were used in the related art.

Development is in progress for the pattern formation by EUV or the likewhile aiming at a resist pattern width of 10 to 15 nm, and theabove-mentioned liquid chemical used in this process is required tofurther exhibit defect inhibitive performance.

As a method for producing a liquid chemical used in pattern formation ofthe related art, JP2015-049395A discloses “a method for producing aresist composition used in a step of manufacturing a semiconductordevice, the method including: cleaning a manufacturing device for aresist composition with a cleaning liquid; removing the cleaning liquidfrom the manufacturing device to be spin-applied to a substrate forevaluation; cleaning the substrate for evaluation until changes indefect density of defects having a size of 100 nm or more in thesubstrate for evaluation before and after application become 0.2defects/cm² or less; and thereafter, producing a resist composition bythe manufacturing device.” JP2015-049395A discloses that pattern defectsand the like were inhibited in a case where ArF exposure was performedusing a liquid chemical (resist composition) produced by this method.

SUMMARY OF THE INVENTION

The inventors of the present invention have found that defects aregenerated in a case where patterns are formed by EUV exposure using aresist composition containing a liquid chemical produced by the aboveproduction method.

Accordingly, an object of the present invention is to provide a liquidchemical from which defects are hardly generated even in a case wherethe liquid chemical is applied to a resist process by EUV exposure, inother words, a liquid chemical exhibiting excellent defect inhibitiveperformance even in a case of being applied to a resist process by EUVexposure.

Another object of the present invention is to provide a method forproducing a liquid chemical.

The inventors of the present invention have conducted intensive studiesto achieve the above-mentioned objects, and as a result, they have foundthat the above-mentioned objects can be achieved by the followingconfigurations.

[1] A liquid chemical comprising: an organic solvent; Fe nanoparticlescontaining a Fe atom and having a particle size of 0.5 to 17 nm; and Pbnanoparticles containing a Pb atom and having a particle size of 0.5 to17 nm, in which a ratio of the number of the Fe nanoparticles containedto the number of the Pb nanoparticles contained is 1.0 to 1.0×10⁴, basedon the number of the particles per unit volume of the liquid chemical.

[2] The liquid chemical according to [1], further comprising Crnanoparticles containing a Cr atom and having a particle size of 0.5 to17 nm, in which a ratio of the number of the Fe nanoparticles containedto the number of the Cr nanoparticles contained is 1.0 to 1.0×10⁴, basedon the number of the particles per unit volume of the liquid chemical.

[3] The liquid chemical according to [1] or [2], further comprising Tinanoparticles containing a Ti atom and having a particle size of 0.5 to17 nm, in which a ratio of the number of the Fe nanoparticles containedto the number of the Ti nanoparticles contained is 1.0 to 1.0×10³, basedon the number of the particles per unit volume of the liquid chemical.

[4] The liquid chemical according to any one of [1] to [3], which is formanufacturing a semiconductor device.

[5] The liquid chemical according to any one of [1] to [4], in which theFe nanoparticles consist of at least one selected from the groupconsisting of particles A consisting of a simple substance of Fe,particles B consisting of an oxide of a Fe atom, and particles Cconsisting of a simple substance of Fe and an oxide of a Fe atom.

[6] The liquid chemical according to [5], in which a ratio of the numberof the particles A contained to a total of the number of the particles Bcontained and the number of the particles C contained is less than 1.0,based on the number of the particles per unit volume of the liquidchemical.

[7] The liquid chemical according to [6], in which the ratio of thenumber of the particles contained is 1.0×10⁻¹ or less.

[8] The liquid chemical according to any one of [1] to [7], furthercomprising an organic compound having a boiling point of 300° C. orhigher.

[9] The liquid chemical according to [8], in which at least some of theFe nanoparticles are particles U containing the organic compound.

[10] The liquid chemical according to [8] or [9], in which at least someof the Fe nanoparticles are the particles U containing the organiccompound and particles V not containing the organic compound, and aratio of the number of the particles U contained to the number of theparticles V contained is 1.0×10¹ or more, based on the number of theparticles per unit volume of the liquid chemical.

[11] A method for producing a liquid chemical, which is for producingthe liquid chemical according to any one of [1] to [10], the methodcomprising a filtration step of filtering a purification targetsubstance containing an organic solvent using a filter to obtain theliquid chemical.

[12] The method for producing a liquid chemical according to [11], inwhich the filtration step is a multi-stage filtration step in which thepurification target substance is passed through two or more kinds offilters different in at least one selected from the group consisting ofa filter material, a pore diameter, and a pore structure.

[13] The method for producing a liquid chemical according to [11] or[12], in which, for the filter, in a case of using one filter, a porediameter of the filter is 5 nm or smaller, and in a case of using two ormore filters, a pore diameter of a filter having a smallest porediameter among the filters is 5 nm or smaller.

According to the present invention, it is possible to provide a liquidchemical exhibiting excellent defect inhibitive performance even in acase of being applied to a resist process by EUV exposure. Anotherobject of the present invention is to provide a method for producing aliquid chemical.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a typical example of apurification device with which a multi-stage filtration step can beperformed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described in detail.

The description of constituent elements described below can be madebased on representative embodiments of the present invention, but thepresent invention is not limited to such embodiments.

Numerical value ranges expressed using “to” in the present specificationmean a range including numerical values described before and after “to”as the lower limit value and the upper limit value.

In addition, in the present invention, “ppm” means “parts-per-million(10⁻⁶),” “ppb” means “parts-per-billion (10⁻⁹),” “ppt” means“parts-per-trillion (10⁻¹²),” and “ppq” means “parts-per-quadrillion(10⁻¹⁵).”

Furthermore, in the indication of a group (atomic group) in the presentinvention, the indication not including substitution or unsubstitutionincludes those having a substituent and also those not having asubstituent within a range not impairing effects of the presentinvention. For example, a “hydrocarbon group” refers to not only ahydrocarbon group not having a substituent (unsubstituted hydrocarbongroup) but also a hydrocarbon group having a substituent (substitutedhydrocarbon group). This also applies to each compound.

Furthermore, the term “radiation” in the present invention means, forexample, far ultraviolet, extreme ultraviolet (EUV), X-rays, electronrays, and the like. Furthermore, in the present invention, light meansactive light rays or radiation. Unless otherwise specified, the term“exposure” in the present invention includes not only exposure to farultraviolet, X-rays, EUV, or the like, but also lithography by particlebeams such as electron rays or ion beams.

Liquid Chemical

A liquid chemical according to an embodiment of the present inventionincludes an organic solvent; Fe nanoparticles containing a Fe atom andhaving a particle size of 0.5 to 17 nm; and Pb nanoparticles containinga Pb atom and having a particle size of 0.5 to 17 nm, in which a ratioof the number of the Fe nanoparticles contained to the number of the Pbnanoparticles contained is 1.0 to 1.0×10⁴, based on the number of theparticles per unit volume of the liquid chemical. Although the mechanismby which the objects of the present invention are achieved by thepresent liquid chemical is not necessarily clarified, the inventors ofthe present invention presume the mechanism as follows. The followingmechanism is presumption, and even in a case where the objects of thepresent invention are achieved by a mechanism other than the followingmechanism, this is included in the scope of the present invention.

The inventors of the present invention have intensively studied causeswhy defects are generated in a case where a liquid chemical is appliedto a resist process by EUV exposure. As a result, they have discoveredfor the first time that, among particles contained in the liquidchemical which have a particle size of 0.5 to 17 nm and contain a metalatom, particles containing a Fe atom (Fe nanoparticles) have uniqueproperties as compared to particles containing other metal atoms, andthis affects defect inhibitive performance of the liquid chemical.

In a process to which EUV exposure is applied, there is a demand fornarrowing a pattern space and a pattern width of a resist, and a pitchof a pattern which is obtained by totalling one pattern width and onepattern space and in which these pattern width and space areperiodically arranged; and a space and a width of a manufactured wiring,and a pitch of a wiring which is obtained by totalling one wiring widthand one wiring space and in which these wiring width and space areperiodically arranged.

Specifically, in many cases, a pattern width and/or a pattern space isabout 10 to 15 nm (in this case, a pattern pitch is 20 to 30 nm in manycases). In such a case, the inventors of the present invention havefound that controlling of finer particles by unit of the number ofparticles is required, which has not been a problem in a process of therelated art.

Among the above-mentioned particles, because metal-containing particleshaving a particle size of smaller than 0.5 nm aggregate more easily andform coarse particles as a result in many cases, these particles areremoved (for example, in a form of being washed away) during a processin many cases. Accordingly, it is presumed that an influence of theseparticles on defect inhibitive performance of the liquid chemical is notso large.

Meanwhile, among the above-mentioned particles, because metal-containingparticles having a particle size of larger than 17 nm are sufficientlylarge as compared to a required resist pitch, these particles areremoved during a process as described above. Accordingly, it is presumedthat an influence of these particles on defect inhibitive performance ofthe liquid chemical is not so large.

Among the particles, according to the findings obtained by the inventorsof the present invention, in a liquid chemical, Fe nanoparticlesassociate with an organic compound in many cases as compared withnanoparticles containing other atoms (particularly, Pb nanoparticles).

The inventors of the present invention have found that an organiccompound in a free state which is present in a liquid chemical causesdefects called spot-like defects. Accordingly, it is presumed thatgeneration of spot-like defects can be inhibited by controlling acontent of Fe nanoparticles in the liquid chemical. In other words, bysetting the number of Fe nanoparticles contained which associate with anorganic compound more easily to 1.0 or more with respect to the numberof Pb nanoparticles contained which are present as a state of notassociating with an organic compound in the liquid chemical in manycases, it is possible to appropriately reduce an amount of organiccompounds in a free state (among compounds, a high-boiling point organiccompound to be described later) in the liquid chemical can be reducedappropriately, as a result, the liquid chemical exhibits excellentdefect inhibitive performance (particularly, spot-like defect inhibitiveperformance).

In addition, it is presumed that Pb nanoparticles, which are present asa state of not associating with an organic compound in the liquidchemical in many cases, have a property allowing particles to be easilyaggregated with each other by metal bonding in a case where the liquidchemical is applied to a substrate, and the like. It is presumed thataggregated particles are a factor that deteriorates uniformity of apattern width. In the liquid chemical according to the embodiment of thepresent invention, since the number of Fe nanoparticles contained withrespect to the number of Pb nanoparticles contained was set to 1.0 ormore, a content of Pb nanoparticles that are relatively easilyaggregated is controlled to a certain value or less, and thereby theliquid chemical exhibits more excellent defect inhibitive performance(particularly, pattern width uniform performance).

Meanwhile, in a case where Fe/Pb is 1.0×10⁴ or less, the liquid chemicalexhibits excellent residue defect inhibitive performance and excellentbridge defect inhibitive performance. Fe has a smaller standardoxidation-reduction potential than Pb, and thus is likely to be presentas an ion in the liquid chemical. Meanwhile, it is presumed that such Feions easily react with dissolved oxygen in the liquid chemical andbecome oxides, thereby causing residue defects. In addition, theabove-described residues are considered to cause bridge defects at thecase of development. The liquid chemical has a Fe/Pb of 1.0×10⁴ or less,and therefore it exhibits excellent residue defect inhibitiveperformance and excellent bridge defect inhibitive performance

Organic Solvent

The liquid chemical includes the organic solvent. A content of theorganic solvent in the liquid chemical is not particularly limited, butin general, it is preferably 98.0% by mass or more, more preferably99.0% by mass or more, even more preferably 99.9% by mass or more, andparticularly preferably 99.99% by mass or more with respect to a totalmass of the liquid chemical. The upper limit thereof is not particularlylimited but is less than 100% by mass in many cases.

As the organic solvent, one kind thereof may be used alone, or two ormore kinds thereof may be used in combination. In a case where two ormore kinds of organic solvents are used in combination, a total contentthereof is preferably within the above-mentioned range.

In the present specification, the organic solvent means a liquid organiccompound contained at a content of more than 10,000 ppm by mass percomponent with respect to a total mass of the liquid chemical. That is,in the present specification, a liquid organic compound contained at acontent of more than 10,000 ppm by mass with respect to a total mass ofthe liquid chemical corresponds to the organic solvent.

In the present specification, the term “liquid” means a substance thatis liquid at 25° C. and atmospheric pressure.

The type of the organic solvent is not particularly limited, and knownorganic solvents can be used. Examples of organic solvents includealkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkylether, lactic acid ethyl ester, alkyl alkoxypropionate, cyclic lactone(preferably having 4 to 10 carbon atoms), a monoketone compound(preferably having 4 to 10 carbon atoms) which may have a ring, alkylenecarbonate, alkyl alkoxyacetate, alkyl pyruvate, and the like.

As the organic solvent, for example, those disclosed in JP2016-057614A,JP2014-219664A, JP2016-138219A, and JP2015-135379A may be used.

As the organic solvent, at least one selected from the group consistingof propylene glycol monomethyl ether, propylene glycol monoethyl ether(PGME), propylene glycol monopropyl ether, propylene glycol monomethylether acetate (PGMEA), ethyl lactate (EL), methyl methoxypropionate,cyclopentanone, cyclohexanone (CHN), γ-butyrolactone, diisoamyl ether,butyl acetate (nBA), isoamyl acetate, isopropanol, 4-methyl-2-pentanol,dimethyl sulfoxide, N-methyl-2-pyrrolidone, diethylene glycol, ethyleneglycol, dipropylene glycol, propylene glycol, ethylene carbonate,propylene carbonate (PC), sulfolane, cycloheptanone, 1-hexanol, decane,and 2-heptanone is preferable. Among the above examples, CHN, PGMEA,PGME, nBA, PC, and a mixture thereof are preferable from the viewpointthat then, it is possible to obtain a liquid chemical exhibiting moreexcellent effects of the present invention.

As the organic solvent, one kind thereof may be used alone, or two ormore kinds thereof may be used in combination.

The type and a content of the organic solvent in the liquid chemical canbe measured using a gas chromatography mass spectrometer.

Fe Nanoparticles

The liquid chemical includes Fe nanoparticles. The Fe nanoparticles areparticles containing a Fe atom and having a particle size of 0.5 to 17nm. A content of the Fe nanoparticles in the liquid chemical is notparticularly limited, but in general, it is preferably 1.0×10⁴ to1.0×10⁷ particles/cm³, and more preferably 1.0×10⁵ to 1.0×10⁶particles/cm³. In a case where a content of the Fe nanoparticles in theliquid chemical is within the above range, the liquid chemical exhibitsmore excellent effects of the present invention.

A content of the Fe nanoparticles in the liquid chemical can be measuredby a method described in Examples, and the particle number (the numberof particles) of the Fe nanoparticles per unit volume of the liquidchemical is obtained by rounding off to two significant figures. Alsofor Pb nanoparticles, Cr nanoparticles, and Ti nanoparticles to bedescribed later, the number of particles per unit volume is obtained bythe same rounding process described above.

As long as the Fe nanoparticles contain a Fe atom, a form thereof is notparticularly limited. Examples of forms include a simple substance ofFe, a compound containing a Fe atom (hereinafter, also referred to as a“Fe compound”), a complex thereof, and the like. In addition, the Fenanoparticles may contain metal atoms other than Fe. The Fenanoparticles refer to particles in which a content (atomic %) of Featoms is largest among all atoms contained in the particles. A method ofelemental analysis of particles is as described in Examples.

The complex is not particularly limited, and examples thereof include aso-called core-shell type particles having a simple substance of Fe, anda Fe compound that covers at least a part of the above-mentioned simplesubstance of Fe; solid solution particles containing a Fe atom and otheratoms; eutectic particles containing a Fe atom and other atoms;aggregate particles of a simple substance of Fe and a Fe compound;aggregate particles of different types of Fe compounds; a Fe compound ofwhich a composition changes continuously or intermittently from aparticle surface toward the center; and the like.

The atom other than a Fe atom contained in a Fe compound is notparticularly limited, and examples thereof include a carbon atom, anoxygen atom, a nitrogen atom, a hydrogen atom, a sulfur atom, aphosphorus atom, and the like. Among the examples, an oxygen atom ispreferable. A form of incorporating an oxygen atom to a Fe compound isnot particularly limited, but an oxide of a Fe atom is more preferable.

The Fe nanoparticles preferably consist of at least one selected fromthe group consisting of particles A consisting of a simple substance ofFe, particles B consisting of an oxide of a Fe atom, and particles Cconsisting of a simple substance of Fe and an oxide of a Fe atom, fromthe viewpoint that then, it is possible to obtain a liquid chemicalexhibiting more excellent effects of the present invention. That is, theFe nanoparticles preferably contain the particles A, and more preferablyconsist of the particles A, the particles B, and/or the particles C. Aratio of the number of the particles A contained, the number of theparticles B contained, and the number of the particles C contained inthe Fe nanoparticles (based on the number of the particles per unitvolume of the liquid chemical) is not particularly limited, but a ratio(hereinafter, also referred to as A/(B+C)) of the number of theparticles A contained to a total of the number of the particles Bcontained and the number of the particles C contained is preferably 1.5or less, more preferably less than 1.0, even more preferably 0.20 orless, and particularly preferably 1.0×10⁻¹ or less; and is preferably1.0×10⁻³ or more and more preferably 1.0×10⁻² or more, from theviewpoint that then, it is possible to obtain a liquid chemicalexhibiting more excellent effects of the present invention.

In a case where A/(B+C) is less than 1.0, the liquid chemical exhibitsmore excellent defect inhibitive performance (residue defect inhibitiveperformance, bridge defect inhibitive performance, pattern width uniformperformance, and spot-like defect inhibitive performance).

Pb Nanoparticles

The liquid chemical includes Pb nanoparticles. The Pb nanoparticles areparticles containing a Pb atom and having a particle size of 0.5 to 17nm. A content of the Pb nanoparticles in the liquid chemical is notparticularly limited, but in general, it is preferably 1.0 to 1.0×10⁵particles/cm³, more preferably 1.0×10¹ to 8.0×10⁴ particles/cm³, evenmore preferably 1.0×10¹ to 5.0×10⁴ particles/cm³, particularlypreferably 1.0×10¹ to 3.0×10⁴ particles/cm³, and most preferably 1.0×10¹to 5.0×10³ particles/cm³.

In a case where a content of the Pb nanoparticles in the liquid chemicalis 1.0×10¹ to 8.0×10⁴ particles/cm³, the liquid chemical exhibits moreexcellent residue defect inhibitive performance, more excellent patternwidth uniform performance, and more excellent spot-like defectinhibitive performance.

In addition, in a case where a content of the Pb nanoparticles in theliquid chemical is 1.0×10¹ to 5.0×10⁴ particles/cm³, the liquid chemicalexhibits more excellent bridge defect inhibitive performance.

Furthermore, in a case where a content of the Pb nanoparticles in theliquid chemical is 1.0×10¹ to 3.0×10⁴ particles/cm³, the liquid chemicalexhibits more excellent residue defect inhibitive performance, moreexcellent pattern width uniform performance, and more excellentspot-like defect inhibitive performance.

Furthermore, in a case where a content of the Pb nanoparticles in theliquid chemical is 1.0×10¹ to 5.0×10³ particles/cm³, the liquid chemicalexhibits more excellent bridge defect inhibitive performance.

A content of the Pb nanoparticles in the liquid chemical can be measuredby a method described in Examples.

As long as the Pb nanoparticles contain a Pb atom, a form thereof is notparticularly limited. Examples of forms include a simple substance ofPb, a compound containing a Pb atom (hereinafter, also referred to as a“Pb compound”), a complex thereof, and the like. In addition, the Pbnanoparticles may contain metal atoms other than Pb. The Pbnanoparticles refer to particles in which a content (atomic %) of Pbatoms is largest among all atoms contained in the particles. A method ofelemental analysis of particles is as described in Examples.

The complex is not particularly limited, and examples thereof include aso-called core-shell type particles having a simple substance of Pb, anda Pb compound that covers at least a part of the above-mentioned simplesubstance of Pb; solid solution particles containing a Pb atom and otheratoms; eutectic particles containing a Pb atom and other atoms;aggregate particles of a simple substance of Pb and a Pb compound;aggregate particles of different types of Pb compounds; a Pb compound ofwhich a composition changes continuously or intermittently from aparticle surface toward the center; and the like.

The atom other than a Pb atom contained in a Pb compound is notparticularly limited, and examples thereof include a carbon atom, anoxygen atom, a nitrogen atom, a hydrogen atom, a sulfur atom, aphosphorus atom, and the like. Among the examples, an oxygen atom ispreferable. A form of incorporating an oxygen atom to a Pb compound isnot particularly limited, but an oxide of a Pb atom is more preferable.

A ratio (hereinafter also referred to as a “Fe/Pb”) of the number of theFe nanoparticles contained to the number of the Pb nanoparticlescontained (particles/cm³) based on the number of the particles per unitvolume of the liquid chemical is 1.0 to 1.0×10⁴, is preferably 3.0 to1.5×10³, and is more preferably 1.0×10¹ to 2.0×10².

In a case where a Fe/Pb is 3.0 or more, the liquid chemical exhibitsmore excellent residue defect inhibitive performance, more excellentbridge defect inhibitive performance, more excellent pattern widthuniform performance, and more excellent spot-like defect inhibitiveperformance.

In a case where a Fe/Pb is 1.0×10¹ or more, the liquid chemical exhibitsmore excellent residue defect inhibitive performance, more excellentpattern width uniform performance, and more excellent spot-like defectinhibitive performance

In a case where a Fe/Pb is 1.5×10³ or less, the liquid chemical exhibitsmore excellent residue defect inhibitive performance, more excellentbridge defect inhibitive performance, more excellent pattern widthuniform performance, and more excellent spot-like defect inhibitiveperformance.

In a case where a Fe/Pb is 2.0×10² or less, the liquid chemical exhibitsmore excellent residue defect inhibitive performance, more excellentbridge defect inhibitive performance, more excellent pattern widthuniform performance, and more excellent spot-like defect inhibitiveperformance.

A Fe/Pb is obtained by rounding off to two significant figures. The sameapplies to Fe/Cr, Fe/Ti, A/(B+C), and U/V.

Other Components

The liquid chemical may include other components other than theabove-described components. Examples of other components include Crnanoparticles, Ti nanoparticles, organic compounds other than theorganic solvent (particularly, an organic compound having a boilingpoint of 300° C. or higher), water, resins, and the like.

Cr Nanoparticles

The liquid chemical preferably includes Cr nanoparticles. The Crnanoparticles are particles containing a Cr atom and having a particlesize of 0.5 to 17 nm. The number of the Cr nanoparticles contained inthe liquid chemical is not particularly limited, but in general, it ispreferably 1.0 to 1.0×10⁶ particles/cm³, more preferably 1.5 to 1.0×10⁵particles/cm³, even more preferably 1.5 to 4.5×10⁴ particles/cm³,particularly preferably 1.0×10² to 1.5×10⁴ particles/cm³, and mostpreferably 1.0×10³ to 7.0×10³ particles/cm³.

In a case where the number of the Cr nanoparticles contained in theliquid chemical is 1.5 to 4.5×10⁴ particles/cm³, the liquid chemicalexhibits more excellent residue defect inhibitive performance, moreexcellent bridge defect inhibitive performance, more excellent patternwidth uniform performance, and more excellent spot-like defectinhibitive performance.

In a case where the number of the Cr nanoparticles contained in theliquid chemical is 1.0×10² to 1.5×10⁴ particles/cm³, the liquid chemicalexhibits more excellent residue defect inhibitive performance, moreexcellent pattern width uniform performance, and more excellentspot-like defect inhibitive performance.

In a case where the number of the Cr nanoparticles contained in theliquid chemical is 1.0×10³ to 7.0×10³ particles/cm³, the liquid chemicalexhibits particularly excellent bridge defect inhibitive performance.

The number of the Cr nanoparticles contained in the liquid chemical canbe measured by a method described in Examples.

A ratio (hereinafter, also referred to as a “Fe/Cr”) of the number ofthe Fe nanoparticles contained per unit volume of the liquid chemical tothe number of the Cr nanoparticles contained (particles/cm³) per unitvolume of the liquid chemical is not particularly limited, but it ispreferably 1.0×10⁻¹ to 2.0×10⁴, more preferably 1.0 to 1.0×10⁴, evenmore preferably 5.0 to 1.4×10³, particularly preferably 1.0×10¹ to1.0×10², and most preferably 5.0×10¹ to 1.0×10², from the viewpoint thatthen, a liquid chemical exhibiting more excellent effects of the presentinvention is obtained.

In a case where a Fe/Cr is 1.0 to 1.0×10⁴, the liquid chemical exhibitsmore excellent bridge defect inhibitive performance.

In a case where a Fe/Cr is 5.0 to 1.4×10³, the liquid chemical exhibitsmore excellent residue defect inhibitive performance, more excellentbridge defect inhibitive performance, more excellent pattern widthuniform performance, and more excellent spot-like defect inhibitiveperformance.

In a case where a Fe/Cr is 10 to 1.0×10², the liquid chemical exhibitsmore excellent residue defect inhibitive performance, more excellentpattern width uniform performance, and more excellent spot-like defectinhibitive performance.

In a case where a Fe/Cr is 50 to 1.0×10², the liquid chemical exhibitsmore excellent bridge defect inhibitive performance.

A form of the Cr nanoparticle is not particularly limited, and examplesof forms include a simple substance of Cr, a compound containing a Cratom (hereinafter, also referred to as a “Cr compound”), a complexthereof, and the like. In addition, the Cr nanoparticles may containmetal atoms other than Cr. The Cr nanoparticles refer to particles inwhich a content (atomic %) of Cr atoms is largest among all atomscontained in the particles. A method of analyzing a composition of theparticles is as described in Examples.

The complex is not particularly limited, and examples thereof include aso-called core-shell type particles having a simple substance of Cr, anda Cr compound that covers at least a part of the above-mentioned simplesubstance of Cr; solid solution particles containing a Cr atom and otheratoms; eutectic particles containing a Cr atom and other atoms;aggregate particles of a simple substance of Cr and a Cr compound;aggregate particles of different types of Cr compounds; a Cr compound ofwhich a composition changes continuously or intermittently from aparticle surface toward the center; and the like.

The atom other than a Cr atom contained in a Cr compound is notparticularly limited, and examples thereof include a carbon atom, anoxygen atom, a nitrogen atom, a hydrogen atom, a sulfur atom, aphosphorus atom, and the like. Among the examples, an oxygen atom ispreferable. A form of incorporating an oxygen atom to a Cr compound isnot particularly limited, but an oxide of a Cr atom is more preferable.

Ti Nanoparticles

The liquid chemical may include Ti nanoparticles. The Ti nanoparticlesare particles containing a Ti atom and having a particle size of 0.5 to17 nm. A content of the Ti nanoparticles in the liquid chemical is notparticularly limited, but in general, it is preferably 1.0 to 3.0×10⁵particles/cm³, more preferably 2.0×10² to 5.0×10⁴ particles/cm³, evenmore preferably 1.0×10³ to 4.0×10⁵ particles/cm³, and particularlypreferably 1.0×10³ to 1.0×10⁵ particles/cm³.

In a case where a content of the Ti nanoparticles in the liquid chemicalis 2.0×10² particles/cm³ or more, the liquid chemical exhibits moreexcellent bridge defect inhibitive performance.

In a case where a content of the Ti nanoparticles in the liquid chemicalis 1.0×10³ particles/cm³ or more, the liquid chemical exhibits moreexcellent residue defect inhibitive performance, more excellent bridgedefect inhibitive performance, more excellent pattern width uniformperformance, and more excellent spot-like defect inhibitive performance.

In a case where a content of the Ti nanoparticles in the liquid chemicalis 5.0×10⁴ particles/cm³ or less, the liquid chemical exhibits moreexcellent residue defect inhibitive performance, more excellent bridgedefect inhibitive performance, more excellent pattern width uniformperformance, and more excellent spot-like defect inhibitive performance.

In a case where a content of the Ti nanoparticles in the liquid chemicalis 4.0×10⁵ particles/cm³ or less, the liquid chemical exhibits moreexcellent residue defect inhibitive performance, more excellent patternwidth uniform performance, and more excellent spot-like defectinhibitive performance.

In a case where a content of the Ti nanoparticles in the liquid chemicalis 1.0×10⁵ particles/cm³ or less, the liquid chemical exhibitsparticularly excellent bridge defect inhibitive performance.

A ratio (hereinafter, also referred to as a “Fe/Ti”) of the number ofthe Fe nanoparticles contained per unit volume of the liquid chemical tothe number of the Ti nanoparticles contained (particles/cm³) per unitvolume of the liquid chemical is not particularly limited, but it ispreferably 1.0×10⁻¹ to 2.0×10⁴, more preferably 1.0 to 1.0×10³, evenmore preferably 3.0 to 1.0×10², and particularly preferably 4.0 to1.0×10², from the viewpoint that then, a liquid chemical exhibiting moreexcellent effects of the present invention is obtained.

In a case where a Fe/Ti in the liquid chemical is 1 or more, the liquidchemical exhibits more excellent bridge defect inhibitive performance.

In a case where a Fe/Ti in the liquid chemical is 3.0 or more, theliquid chemical exhibits more excellent residue defect inhibitiveperformance, more excellent bridge defect inhibitive performance, moreexcellent pattern width uniform performance, and more excellentspot-like defect inhibitive performance.

In a case where a Fe/Ti in the liquid chemical is 4.0 or more, theliquid chemical exhibits particularly excellent bridge defect inhibitiveperformance.

In a case where a Fe/Ti in the liquid chemical is 1.0×10³ or less, theliquid chemical exhibits more excellent defect inhibitive performance.

In a case where a Fe/Ti in the liquid chemical is 1.0×10² or less, theliquid chemical exhibits more excellent residue defect inhibitiveperformance, more excellent bridge defect inhibitive performance, moreexcellent pattern width uniform performance, and more excellentspot-like defect inhibitive performance.

A form of the Ti nanoparticle is not particularly limited, and examplesof forms include a simple substance of Ti, a compound containing a Tiatom (hereinafter, also referred to as a “Ti compound”), a complexthereof, and the like. In addition, the Ti nanoparticles may containmetal atoms other than Ti. The Ti nanoparticles refer to particles inwhich a content (atomic %) of Ti atoms is largest among all atomscontained in the particles. A method of elemental analysis of particlesis as described in Examples.

The complex is not particularly limited, and examples thereof include aso-called core-shell type particles having a simple substance of Ti, anda Ti compound that covers at least a part of the above-mentioned simplesubstance of Ti; solid solution particles containing a Ti atom and otheratoms; eutectic particles containing a Ti atom and other atoms;aggregate particles of a simple substance of Ti and a Ti compound;aggregate particles of different types of Ti compounds; a Ti compound ofwhich a composition changes continuously or intermittently from aparticle surface toward the center; and the like.

The atom other than a Ti atom contained in a Ti compound is notparticularly limited, and examples thereof include a carbon atom, anoxygen atom, a nitrogen atom, a hydrogen atom, a sulfur atom, aphosphorus atom, and the like. Among the examples, an oxygen atom ispreferable. A form of incorporating an oxygen atom to a Ti compound isnot particularly limited, but an oxide of a Ti atom is more preferable.

Organic Compound Other Than Organic Solvent

The liquid chemical may include an organic compound other than theorganic solvent (hereinafter, also referred to as a “specific organiccompound”). In the present specification, the specific organic compoundis a compound different from the organic solvent contained in the liquidchemical, and means an organic compound contained at a content of 10,000mass ppm or less with respect to a total mass of the liquid chemical.That is, in the present specification, the organic compound contained ata content of 10,000 ppm by mass or less with respect to a total mass ofthe liquid chemical corresponds to the specific organic compound anddoes not correspond to the organic solvent.

In a case where a plurality of types of organic compounds are containedin the liquid chemical, and in a case where each of the organiccompounds is contained at the above-mentioned content of 10,000 mass ppmor less, the respective organic compounds correspond to the specificorganic compound.

The specific organic compound may be added to the liquid chemical or maybe unintentionally mixed in a step of producing the liquid chemical.Examples of cases in which the specific organic compound isunintentionally mixed in a step of producing the liquid chemical includea case in which the specific organic compound is contained in a rawmaterial (for example, an organic solvent) used for producing the liquidchemical, a case in which the specific organic compound is mixed (forexample, contamination) in a step of producing the liquid chemical, andthe like, but examples are not limited thereto.

A content of the specific organic compound in the liquid chemical can bemeasured using gas chromatography mass spectrometer (GCMS).

The number of carbon atoms of the specific organic compound is notparticularly limited, but it is preferably 8 or more and more preferably12 or more from the viewpoint that then, the liquid chemical exhibitsmore excellent effects of the present invention. The upper limit of thenumber of carbon atoms is not particularly limited, but it is preferably30 or less.

The specific organic compound may be, for example, a by-productgenerated due to synthesis of the organic solvent and/or an unreactedraw material (hereinafter, also referred to as “by-product and thelike”), and the like.

Examples of by-products and the like include compounds represented byFormulas I to V.

In Formula I, R₁ and R₂ each independently represent an alkyl group or acycloalkyl group, or are bonded to each other to form a ring.

As an alkyl group or a cycloalkyl group represented by R₁ and R₂, analkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 6to 12 carbon atoms is preferable, and an alkyl group having 1 to 8carbon atoms or a cycloalkyl group having 6 to 8 carbon atoms is morepreferable.

A ring to be formed by bonding of R₁ and R₂ to each other is a lactonering, is preferably a 4- to 9-membered lactone ring, and is morepreferably a 4- to 6-membered lactone ring.

R₁ and R₂ preferably satisfy a relationship in which the compoundrepresented by Formula I has 8 or more carbon atoms.

In Formula II, R₃ and R₄ each independently represent a hydrogen atom,an alkyl group, an alkenyl group, a cycloalkyl group, or a cycloalkenylgroup, or are bonded to each other to form a ring. Where not both R₃ andR₄ are hydrogen atoms.

As an alkyl group represented by R₃ and R₄, for example, an alkyl grouphaving 1 to 12 carbon atoms is preferable, and an alkyl group having 1to 8 carbon atoms is more preferable.

As an alkenyl group represented by R₃ and R₄, for example, an alkenylgroup having 2 to 12 carbon atoms is preferable, and an alkenyl grouphaving 2 to 8 carbon atoms is more preferable.

As a cycloalkyl group represented by R₃ and R₄, a cycloalkyl grouphaving 6 to 12 carbon atoms is preferable, and a cycloalkyl group having6 to 8 carbon atoms is more preferable.

As a cycloalkenyl group represented by R₃ and R₄, for example, acycloalkenyl group having 3 to 12 carbon atoms is preferable, and acycloalkenyl group having 6 to 8 carbon atoms is more preferable.

A ring to be formed by bonding of R₃ and R₄ to each other has a cyclicketone structure, and it may be a saturated cyclic ketone or anunsaturated cyclic ketone. This cyclic ketone is preferably a 6- to10-membered ring and more preferably a 6- to 8-membered ring.

R₃ and R₄ preferably satisfy a relationship in which the compoundrepresented by Formula II has 8 or more carbon atoms.

In Formula III, R₅ represents an alkyl group or a cycloalkyl group.

An alkyl group represented by R₅ is preferably an alkyl group having 6or more carbon atoms, more preferably an alkyl group having 6 to 12carbon atoms, and even more preferably an alkyl group having 6 to 10carbon atoms.

The alkyl group may have an ether bond in a chain, or may have asubstituent such as a hydroxy group.

A cycloalkyl group represented by R₅ is preferably a cycloalkyl grouphaving 6 or more carbon atoms, more preferably a cycloalkyl group having6 to 12 carbon atoms, and even more preferably a cycloalkyl group having6 to 10 carbon atoms.

In Formula IV, R₆ and R₇ each independently represent an alkyl group ora cycloalkyl group, or are bonded to each other to form a ring.

As an alkyl group represented by R₆ and R₇, an alkyl group having 1 to12 carbon atoms is preferable, and an alkyl group having 1 to 8 carbonatoms is more preferable.

As a cycloalkyl group represented by R₆ and R₇, a cycloalkyl grouphaving 6 to 12 carbon atoms is preferable, and a cycloalkyl group having6 to 8 carbon atoms is more preferable.

A ring to be formed by bonding of R₆ and R₇ to each other has a cyclicether structure. This cyclic ether structure is preferably a 4- to8-membered ring and more preferably a 5- to 7-membered ring.

R₆ and R₇ preferably satisfy a relationship in which the compoundrepresented by Formula IV has 8 or more carbon atoms.

In Formula V, R₈ and R₉ each independently represent an alkyl group or acycloalkyl group, or are bonded to each other to form a ring. Lrepresents a single bond or an alkylene group.

As an alkyl group represented by R₈ and R₉, for example, an alkyl grouphaving 6 to 12 carbon atoms is preferable, and an alkyl group having 6to 10 carbon atoms is more preferable.

As a cycloalkyl group represented by R₈ and R₉, a cycloalkyl grouphaving 6 to 12 carbon atoms is preferable, and a cycloalkyl group having6 to 10 carbon atoms is more preferable.

A ring to be formed by bonding of R₈ and R₉ to each other has a cyclicdiketone structure. This cyclic diketone structure is preferably a 6- to12-membered ring and more preferably a 6- to 10-membered ring.

As an alkylene group represented by L, for example, an alkylene grouphaving 1 to 12 carbon atoms is preferable, and an alkylene group having1 to 10 carbon atoms is more preferable.

R₈, R₉, and L satisfy a relationship in which the compound representedby Formula V has 8 or more carbon atoms.

Although not particularly limited, in a case where the organic solventis an amide compound, an imide compound, and a sulfoxide compound, inone aspect, an amide compound, an imide compound, and a sulfoxidecompound which have 6 or more carbon atoms are used. In addition,examples of specific organic compounds include the following compounds.

In addition, examples of specific organic compounds include antioxidantssuch as dibutylhydroxytoluene (BHT), distearyl thiodipropionate (DSTP),4,4′ -butylidenebis-(6-t-butyl-3-methylphenol),2,2′-methylenebis-(4-ethyl-6-t-butylphenol), and an antioxidantdisclosed in JP2015-200775A; unreacted raw materials; structural isomersand by-products produced during production of organic solvents; elutedsubstances (for example, a plasticizer eluted from a rubber member suchas an O-ring) from members and the like constituting a production devicefor organic solvents; and the like.

Furthermore, examples of specific organic compounds include dioctylphthalate (DOP), bis(2-ethylhexyl) phthalate (DEHP), bis(2-propylheptyl)phthalate (DPHP), dibutyl phthalate (DBP), benzyl butyl phthalate(BBzP), diisodecyl phthalate (DIDP), diisooctyl phthalate (DIOP),diethyl phthalate (DEP), diisobutyl phthalate (DIBP), dihexyl phthalate,diisononyl phthalate (DINP), tris(2-ethylhexyl) trimellitate (TEHTM),tris(n-octyl-n-decyl) trimellitate (ATM), bis(2-ethylhexyl) adipate(DEHA), monomethyl adipate (MMAD), dioctyl adipate (DOA), dibutylsebacate (DBS), dibutyl maleate (DBM), diisobutyl maleate (DIBM),azelaic acid ester, benzoic acid ester, terephthalate (for example,dioctyl terephthalate (DEHT)), 1,2-cyclohexane dicarboxylic aciddiisononyl ester (DINCH), epoxidized vegetable oils, sulfonamide (forexample, N-(2-hydroxypropyl)benzenesulfonamide (HPBSA),N-(n-butyl)benzenesulfonamide (BBSA-NBBS)), organophosphate ester (forexample, tricresyl phosphate (TCP), tributyl phosphate (TBP)),acetylated monoglyceride, triethyl citrate (TEC), acetyl triethylcitrate (ATEC), tributyl citrate (TBC), acetyl tributyl citrate (ATBC),trioctyl citrate (TOC), trioctyl acetyl citrate (ATOC), trihexyl citrate(THC), acetyl trihexyl citrate (ATHC), epoxidized soybean oil, ethylenepropylene rubber, polybutene, an addition polymer of5-ethylidene-2-norbornene, and polymer plasticizers exemplified below.

It is presumed that these specific organic compounds are mixed into apurification target substance or the liquid chemical from a filter, apipe, a tank, an O-ring, a container, or the like which comes intocontact therewith in a purification step. In particular, compounds otherthan alkyl olefins are associated generation of bridge defects.

Organic Compound Having Boiling Point of 300° C. or Higher

The liquid chemical may include a specific organic compound having aboiling point of 300° C. or higher (a high-boiling point organiccompound). In a case where the liquid chemical includes the organiccompound having a boiling point of 300° C. or higher, it hardlyvolatilizes during a photolithography process because of a high boilingpoint. For this reason, it is necessary to strictly control a content,an existence form thereof, and the like of a high-boiling point organiccompound in the liquid chemical to obtain a liquid chemical exhibitingexcellent defect inhibitive performance.

As such high-boiling point organic compounds, for example, dioctylphthalate (a boiling point of 385° C.), diisononyl phthalate (a boilingpoint of 403° C.), dioctyl adipate (a boiling point of 335° C.), dibutylphthalate (a boiling point of 340° C.), ethylene propylene rubber (aboiling point of 300° C. to 450° C.), and the like have been confirmed.

The inventors of the present invention have found that there are variousforms in a case where a high-boiling point organic compound is containedin the liquid chemical. Examples of existence forms of the high-boilingpoint organic compound in the liquid chemical include particles in whichparticles consisting of a metal atom or a metallic compound areaggregate with particles of a high-boiling point organic compound;particles in which particles consisting of a metal atom or a metalliccompound, and a high-boiling point organic compound disposed to cover atleast a part of the particles are included; particles formed bycoordination bonding between a metal atom and a high-boiling pointorganic compound; and the like.

Among the examples, the Fe nanoparticles (particles U) containing anorganic compound (preferably, a high-boiling point organic compound) areexemplified as a form having a large influence on defect inhibitiveperformance of the liquid chemical. The inventors of the presentinvention have found that defect inhibitive performance of the liquidchemical is dramatically improved by controlling a content of theparticles U in the liquid chemical.

Although the reason for this is not necessarily clear, because theparticles U contain an organic compound (preferably, a high-boilingpoint organic compound), surface free energy of the particles U easilybecomes relatively lower than that of the Fe nanoparticles notcontaining the organic compound. Such particles U are unlikely to remainon a substrate that has been treated with the liquid chemical, and evenin a case where the particles remain thereon, they are easily removed ina case where they come into contact with the liquid chemical again. Forexample, in a case where the liquid chemical is used as a developer anda rinsing solution, the particles U are further unlikely to remain on asubstrate during development and are further more easily removed byrinsing or the like. That is, as a result, both particles containing anorganic compound (preferably, a high-boiling point organic compound) andparticles containing a Fe atom are more easily removed.

In addition, it is presumed that the particles U having lower surfaceenergy are unlikely to remain on a substrate because a resist film isgenerally water-repellent in many cases.

According to the study of the inventors of the present invention, theyhave found that a liquid chemical exhibiting more excellent effects ofthe present invention is obtained by controlling the number of theparticles V contained which do not contain an organic compound(preferably, a high-boiling point organic compound), and the number ofthe particles U contained per unit volume of the liquid chemical.

That is, a ratio of the number of the particles U contained to thenumber of the particles V contained based on the number of the particlesper unit volume of the liquid chemical is preferably 10 or more, morepreferably 100 or less, even more preferably 50 or less, still morepreferably 35 or less, and particularly preferably 25 or less from theviewpoint that then, a liquid chemical exhibiting more excellent effectsof the present invention is obtained.

Water

The liquid chemical may include water. Water is not particularlylimited, and for example, distilled water, ion exchange water, purewater, and the like can be used. Water is not included in theabove-mentioned organic impurities.

Water may be added to the liquid chemical or may be unintentionallymixed into the liquid chemical in a step of producing the liquidchemical. Examples of cases in which water is unintentionally mixed in astep of producing the liquid chemical include a case in which water iscontained in a raw material (for example, an organic solvent) used forproducing the liquid chemical, a case in which water is mixed (forexample, contamination) in a step of producing the liquid chemical, andthe like, but examples are not limited thereto.

A content of water in the liquid chemical is not particularly limited,but in general, it is preferably 0.05% to 2.0% by mass with respect to atotal mass of the liquid chemical. A content of water in the liquidchemical refers to a content of water measured using a device based on aKarl Fischer moisture measurement method as measurement principle.

Resin

The liquid chemical may further include a resin. As the resin, a resin Phaving a group that is decomposed by the action of an acid to generate apolar group is preferable. As the resin, a resin, which has a repeatingunit represented by Formula (AI) and which is a resin in whichsolubility in a developer containing an organic solvent as a maincomponent is reduced by the action of an acid, is more preferable. Theresin having a repeating unit represented by Formula (AI) has a groupthat is decomposed by the action of an acid to generate analkali-soluble group (hereinafter, also referred to as an“acid-decomposable group”).

Examples of polar groups include an alkali-soluble group. Examples ofalkali-soluble groups include a carboxy group, a fluorinated alcoholgroup (preferably a hexafluoroisopropanol group), a phenolic hydroxylgroup, and a sulfo group.

A polar group in the acid-decomposable group is protected by a leavinggroup assisted by an acid (acid leaving group). Examples of acid leavinggroups include —C(R₃₆)(R₃₇)(R₃₈), —C(R₃₆)(R₃₇)(OR₃₉), and—C(R₀₁)(R₀₂)(OR₃₉), and the like.

In the formula, R₃₆ to R₃₉ each independently represent an alkyl group,a cycloalkyl group, an aryl group, an aralkyl group, or an alkenylgroup. R₃₆ and R₃₇ may be bonded to each other to form a ring.

R₀₁ and R₀₂ each independently represent a hydrogen atom, an alkylgroup, a cycloalkyl group, an aryl group, an aralkyl group, or analkenyl group.

Hereinafter, the resin P in which solubility in a developer containingan organic solvent as a main component is reduced by the action of anacid will be described in detail.

Formula (AI): Repeating Unit Having Acid-Decomposable Group

The resin P preferably contains a repeating unit represented by Formula(AI).

In Formula (AI),

Xa₁ represents a hydrogen atom, or an alkyl group which may have asubstituent;

T represents a single bond or a divalent linking group; and

Ra₁ to Ra₃ each independently represent a (linear or branched) alkylgroup or a (monocyclic or polycyclic) cycloalkyl group,

where two of Ra₁ to Ra₃ may be bonded to each other to form a(monocyclic or polycyclic) cycloalkyl group.

Examples of alkyl groups which may have a substituent and is representedby Xa₁ include a methyl group and a group represented by —CH₂—R₁₁. R₁₁represents a halogen atom (such as a fluorine atom), a hydroxyl group,or a monovalent organic group.

Xa₁ is preferably a hydrogen atom, a methyl group, a trifluoromethylgroup, or a hydroxymethyl group.

Examples of divalent linking groups for T include an alkylene group, a—COO-Rt- group, a —O-Rt- group, and the like. In the formula, Rtrepresents an alkylene group or a cycloalkylene group.

T is preferably a single bond or a —COO-Rt- group. Rt is preferably analkylene group having 1 to 5 carbon atoms and is more preferably a —CH₂—group, a —(CH₂)₂— group, or a —(CH₂)₃— group.

An alkyl group for Ra₁ to Ra₃ preferably has 1 to 4 carbon atoms.

As a cycloalkyl group for Ra₁ to Ra₃, monocyclic cycloalkyl groups suchas a cyclopentyl group or a cyclohexyl group; or polycyclic cycloalkylgroups such as a norbornyl group, a tetracyclodecanyl group, atetracyclododecanyl group, or an adamantyl group are preferable.

As a cycloalkyl group formed by bonding of two of Ra₁ to Ra₃ to eachother, monocyclic cycloalkyl groups such as a cyclopentyl group or acyclohexyl group; or polycyclic cycloalkyl groups such as a norbornylgroup, a tetracyclodecanyl group, a tetracyclododecanyl group, or anadamantyl group are preferable. A monocyclic cycloalkyl group having 5to 6 carbon atoms is more preferable.

In the above-mentioned cycloalkyl group formed by bonding of two of Ra₁to Ra₃ to each other, for example, one of methylene groups constitutinga ring may be substituted by a hetero atom such as an oxygen atom, or bya group having a hetero atom such as a carbonyl group.

In the repeating unit represented by Formula (AI), for example, anaspect is preferable, in which Ra₁ is a methyl group or an ethyl group,and Ra₂ and Ra₃ are boned to each other to form the above-describedcycloalkyl group.

Each of the above groups may have a substituent. Examples ofsubstituents include an alkyl group (having 1 to 4 carbon atoms), ahalogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbonatoms), a carboxy group, an alkoxycarbonyl group (having 2 to 6 carbonatoms), and the like, where the number of carbon atoms is preferably 8or less.

A content of the repeating unit represented by Formula (AI) ispreferably 20 to 90 mol %, more preferably 25 to 85 mol %, and even morepreferably 30 to 80 mol % with respect to all repeating units in theresin P.

Repeating Unit Having Lactone Structure

In addition, the resin P preferably contains a repeating unit Q having alactone structure.

The repeating unit Q having a lactone structure preferably has a lactonestructure in a side chain, and it is more preferably a repeating unitderived from a (meth)acrylic acid derivative monomer.

As the repeating unit Q having a lactone structure, one kind thereof maybe used alone, or two or more kinds thereof may be used in combination,but it is preferable to use one kind alone.

A content of the repeating unit Q having a lactone structure ispreferably 3 to 80 mol % and more preferably 3 to 60 mol % with respectto all repeating units in the resin P.

The lactone structure is preferably a 5- to 7-membered lactonestructure, and is more preferably a structure in which another ringstructure is condensed with a 5- to 7-membered lactone structure to forma bicyclo structure or a Spiro structure.

The lactone structure preferably has a repeating unit having a lactonestructure represented by any of Formulas (LC1-1) to (LC1-17). Thelactone structure is preferably a lactone structure represented byFormula (LC1-1), Formula (LC1-4), Formula (LC1-5), or Formula (LC1-8),and is more preferably a lactone structure represented by Formula(LC1-4).

A portion of the lactone structure may have a substituent (Rb₂).Preferable examples of substituents (Rb₂) include an alkyl group having1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, analkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having2 to 8 carbon atoms, a carboxy group, a halogen atom, a hydroxyl group,a cyano group, an acid-decomposable group, and the like. n₂ representsan integer of 0 to 4. In a case where n₂ is 2 or more, a plurality ofsubstituents (Rb₂) may be the same as or different from each other, or aplurality of substituents (Rb₂) may be bonded to each other to form aring.

Repeating Unit Having Phenolic Hydroxyl Group

The resin P may contain a repeating unit having a phenolic hydroxylgroup.

Examples of repeating units having a phenolic hydroxyl group include arepeating unit represented by General Formula (I).

In the formula,

R₄₁, R₄₂, and R₄₃ each independently represent a hydrogen atom, an alkylgroup, a halogen atom, a cyano group, or an alkoxycarbonyl group, whereR₄₂ may be bonded to Ar₄ to form a ring, and in this case, R₄₂represents a single bond or an alkylene group.

X₄ represents a single bond, —COO—, or —CONR₆₄—, and R₆₄ represents ahydrogen atom or an alkyl group.

L₄ represents a single bond or an alkylene group.

Ar₄ represents a (n+1)-valent aromatic ring group, and in a case whereAr₄ is bonded to R₄₂ to form a ring, Ar₄ represents an (n+2)-valentaromatic ring group.

n represents an integer of 1 to 5.

As an alkyl group for R₄₁, R₄₂, and R₄₃ in General Formula (I), an alkylgroup having 20 or less carbon atoms is preferable, an alkyl grouphaving 8 or less carbon atoms is more preferable, and an alkyl grouphaving 3 or less carbon atoms is even more preferable, where alkylgroups may have a substituent, and examples of alkyl groups include amethyl group, an ethyl group, a propyl group, an isopropyl group, ann-butyl group, a sec-butyl group, a hexyl group, a 2-ethylhexyl group,an octyl group, a dodecyl group, and the like.

A cycloalkyl group for R₄₁, R₄₂, and R₄₃ in General Formula (I) may be amonocyclic type or a polycyclic type. The cycloalkyl group is preferablya monocyclic cycloalkyl group such as a cyclopropyl group, a cyclopentylgroup, and a cyclohexyl group, where the cycloalkyl group has 3 to 8carbon atoms and may have a substituent.

Examples of halogen atoms for R₄₁, R₄₂, and R₄₃ in General Formula (I)include a fluorine atom, a chlorine atom, a bromine atom, and an iodineatom, where a fluorine atom is preferable.

As an alkyl group contained in an alkoxycarbonyl group for R₄₁, R₄₂, andR₄₃ in General Formula (I), the same as those described for theabove-described alkyl group in R₄₁, R₄₂, and R₄₃ are preferable.

Examples of substituents in each of the above groups include an alkylgroup, a cycloalkyl group, an aryl group, an amino group, an amidegroup, a ureido group, a urethane group, a hydroxy group, a carboxygroup, a halogen atom, an alkoxy group, a thioether group, an acylgroup, an acyloxy group, an alkoxycarbonyl group, a cyano group, a nitrogroup, and the like, where the substituent preferably has 8 or lesscarbon atoms.

Ar₄ represents an (n+1)-valent aromatic ring group. Examples of divalentaromatic ring groups in a case where n is 1 include arylene groups suchas a phenylene group, a tolylene group, a naphthylene group, and ananthracenylene group, where an arylene group has 6 to 18 carbon atomsand may have a substituent; and aromatic ring groups including aheterocyclic ring such as thiophene, furan, pyrrole, benzothiophene,benzofuran, benzopyrrole, triazine, imidazole, benzimidazole, triazole,thiadiazole, and thiazole.

Specific examples of (n+1)-valent aromatic ring groups in a case where nis an integer of 2 or more include groups in which (n−1) arbitraryhydrogen atoms have been removed from the above-described specificexamples of the divalent aromatic ring groups.

The (n+1)-valent aromatic ring group may further have a substituent.

Examples of substituents that may be included in the above-mentionedalkyl group, cycloalkyl group, alkoxycarbonyl group, alkylene group, and(n+1)-valent aromatic ring group include alkyl groups exemplified forR₄₁, R₄₂, and R₄₃ in General Formula (I); alkoxy groups such as amethoxy group, an ethoxy group, a hydroxyethoxy group, a propoxy group,a hydroxypropoxy group, and a butoxy group; and aryl groups such as aphenyl group.

As an alkyl group for R₆₄ in —CONR₆₄— (where R₆₄ represents a hydrogenatom or an alkyl group) represented by X₄, an alkyl group having 20 orless carbon atoms is preferable, and an alkyl group having 8 or lesscarbon atoms is more preferable, where alkyl groups may have asubstituent, and examples of alkyl groups include a methyl group, anethyl group, a propyl group, an isopropyl group, an n-butyl group, asec-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, adodecyl group, and the like.

X₄ is preferably a single bond, —COO—, or —CONH—, and is more preferablya single bond or —COO—.

An alkylene group for L₄ is preferably an alkylene group such as amethylene group, an ethylene group, a propylene group, a butylene group,a hexylene group, and an octylene group, where an alkylene group has 1to 8 carbon atoms and may have a substituent.

Ar₄ is preferably an aromatic ring group which has 6 to 18 carbon atomsand may have a substituent, and is more preferably a benzene ring group,a naphthalene ring group, or a biphenylene ring group.

The repeating unit represented by General Formula (I) preferably has ahydroxystyrene structure. That is, Ar₄ is preferably a benzene ringgroup.

A content of the repeating unit having a phenolic hydroxyl group ispreferably 0 to 50 mol %, more preferably 0 to 45 mol %, and even morepreferably 0 to 40 mol % with respect to all repeating units in theresin P.

Repeating Unit Containing Organic Group Having Polar Group

The resin P may further contain a repeating unit containing an organicgroup having a polar group, in particular, a repeating unit having analicyclic hydrocarbon structure substituted by a polar group. Thereby,adhesiveness to substrates and affinity for developers are improved.

The alicyclic hydrocarbon structure substituted by a polar group ispreferably an adamantyl group, a diamantyl group, or a norbornane group.The polar group is preferably a hydroxyl group or a cyano group.

In a case where the resin P contains the repeating unit containing anorganic group having a polar group, a content thereof is preferably 1 to50 mol %, more preferably 1 to 30 mol %, even more preferably 5 to 25mol %, and particularly preferably 5 to 20 mol % with respect to allrepeating units in the resin P.

Repeating Unit Represented by General Formula (VI)

The resin P may contain a repeating unit represented by General Formula(VI).

In General Formula (VI),

R₆₁, R₆₂, and R₆₃ each independently represent a hydrogen atom, an alkylgroup, a cycloalkyl group, a halogen atom, a cyano group, or analkoxycarbonyl group, where R₆₂ may be bonded to Ar₆ to form a ring, andin this case, R₆₂ represents a single bond or an alkylene group;

X₆ represents a single bond, —COO—, or —CONR₆₄—; R₆₄ represents ahydrogen atom or an alkyl group;

L₆ represents a single bond or an alkylene group;

Ar₆ represents a (n+1)-valent aromatic ring group, and in a case whereAr₆ is bonded to R₆₂ to form a ring, Ar₆ represents an (n+2)-valentaromatic ring group;

Y₂'s each independently represent a hydrogen atom, or a leaving groupassisted by the action of an acid in a case where n≥2, where at leastone of Y₂'s represents a leaving group assisted by the action of anacid; and

n represents an integer of 1 to 4.

As a leaving group Y₂ assisted by the action of an acid, a structurerepresented by General Formula (VI-A) is preferable.

L₁ and L₂ each independently represent a hydrogen atom, an alkyl group,a cycloalkyl group, an aryl group, or a group in which an alkylene groupand an aryl group are combined.

M represents a single bond or a divalent linking group.

Q represents an alkyl group, a cycloalkyl group which may contain ahetero atom, an aryl group which may contain a hetero atom, an aminogroup, an ammonium group, a mercapto group, a cyano group, or analdehyde group.

At least two of Q, M, or L₁ may be bonded to each other to form a ring(preferably a 5- or 6-membered ring).

The repeating unit represented by General Formula (VI) is preferably arepeating unit represented by General Formula (3).

In General Formula (3),

Ar₃ represents an aromatic ring group;

R₃ represents a hydrogen atom, an alkyl group, a cycloalkyl group, anaryl group, an aralkyl group, an alkoxy group, an acyl group, or aheterocyclic group;

M₃ represents a single bond or a divalent linking group; and

Q₃ represents an alkyl group, a cycloalkyl group, an aryl group, or aheterocyclic group,

where at least two of Q₃, M₃, or R₃ may be bonded to each other to forma ring.

The aromatic ring group represented by Ar₃ is the same as Ar₆ in GeneralFormula (VI) in a case where n in General Formula (VI) is 1, and thearomatic ring group is preferably a phenylene group or a naphthylenegroup, and is more preferably a phenylene group.

Repeating Unit Having Silicon Atom in Side Chain

The resin P may further contain a repeating unit having a silicon atomin a side chain. Examples of repeating units having a silicon atom in aside chain include a (meth)acrylate-based repeating unit having asilicon atom, a vinyl-based repeating unit having a silicon atom, andthe like. The repeating unit having a silicon atom in and side chain istypically a repeating unit having a group having a silicon atom in aside chain. Examples of groups having a silicon atom include atrimethylsilyl group, a triethylsilyl group, a triphenylsilyl group, atricyclohexylsilyl group, a tristrimethylsiloxysilyl group, atristrimethylsilylsilyl group, a methylbistrimethylsilylsilyl group, amethylbistrimethylsiloxysilyl group, a dimethyltrimethylsilylsilylgroup, and a dimethyltrimethylsiloxysilyl group; cyclic or linearpolysiloxanes, or a cage-type, ladder-type, or random-typesilsesquioxane structures which are shown below; and the like. In theformula, R and R¹ each independently represent a monovalent substituent.The symbol “*” represents a bond.

The repeating unit having the above group is preferably, for example, arepeating unit derived from an acrylate compound or a methacrylatecompound which has the above group, or a repeating unit derived from acompound having the above group and a vinyl group.

In a case where the resin P has the repeating unit having a silicon atomin a side chain, a content thereof is preferably 1 to 30 mol %, morepreferably 5 to 25 mol %, and even more preferably 5 to 20 mol % withrespect to all repeating units in the resin P.

A weight-average molecular weight of the resin P is preferably 1,000 to200,000, more preferably 3,000 to 20,000, and even more preferably 5,000to 15,000 as a polystyrene equivalent value by gel permeationchromatography (GPC). In a case where a weight-average molecular weightis 1,000 to 200,000, it is possible to prevent a deterioration of heatresistance and dry etching resistance, and to prevent a deterioration ofdevelopability, and a deterioration of film formability due to increasedviscosity.

A dispersity (molecular weight distribution) is generally 1 to 5, ispreferably 1 to 3, is more preferably 1.2 to 3.0, and is even morepreferably 1.2 to 2.0.

In the liquid chemical, a content of the resin P is preferably 50% to99.9% by mass and more preferably 60% to 99.0% by mass with respect to atotal solid content.

In addition, in the liquid chemical, as the resin P, one kind thereofmay be used alone, or plural kinds thereof may be used in combination.

As other components (for example, acid-generating agents, basiccompounds, quenchers, hydrophobic resins, surfactants, solvents, and thelike) contained in the liquid chemical, any known components can beused. Examples of other components include components contained in anactinic ray-sensitive or radiation-sensitive resin composition disclosedin JP2013-195844A, JP2016-057645A, JP2015-207006A, WO2014/148241A,JP2016-188385A, JP2017-219818A, and the like.

Use Applications of Liquid Chemical

The liquid chemical according to the above embodiment is preferably usedfor manufacturing a semiconductor device. In particular, it is morepreferably used for forming a fine pattern with a node of 10 nm or less(for example, a step including pattern formation using EUV).

The liquid chemical according to the above embodiment is more preferablyused as a liquid chemical (a pre-wetting solution, a developer, arinsing solution, a solvent for resist solution, a peeling solution, andthe like) which is used in a process for a resist in which a patternwidth and/or a pattern space is 17 nm or less (preferably 15 nm or lessand more preferably 12 nm or less), and/or a wiring width to be obtainedand/or a wiring space to be obtained is 17 nm or less. In other words,the liquid chemical according to the above embodiment is more preferablyused as a liquid chemical for manufacturing a semiconductor device thatis manufactured using a resist film in which a pattern width and/or apattern space is 17 nm or less.

Specifically, the liquid chemical is used for treating an organicsubstance in a step of manufacturing a semiconductor device, including alithography step, an etching step, an ion implantation step, a peelingstep, and the like after completing the respective steps or beforeproceeding to the next step. Specifically, the liquid chemical issuitably used as a resist solution, a pre-wetting solution, a developer,a rinsing solution, a peeling solution, and the like. For example, theliquid chemical can be used for rinsing an edge line of a semiconductorsubstrate before and after resist application.

In addition, the liquid chemical can be used as a dilute solution of aresin contained in a resist solution, and a solvent contained in aresist solution. Furthermore, the liquid chemical may be diluted withother organic solvents and/or water and the like.

Furthermore, the liquid chemical can be used for other use applicationsother than manufacture of semiconductor devices, and can also be used asa developer for polyimide, a resist for sensors, a resist for lenses; arinsing solution; and the like.

Furthermore, the liquid chemical can be used as a solvent for medicaluse applications or cleaning use applications. In particular, the liquidchemical can be suitably used for cleaning containers, piping,substrates (such as wafers and glass), and the like.

Among the above examples, the present liquid chemical exhibits moreexcellent effects in a case of being adopted as a pre-wetting solution,a developer, and a rinsing solution in pattern formation using extremeultraviolet (EUV).

Method for Producing Liquid Chemical

A method for producing the above-described liquid chemical is notparticularly limited, and known production methods can be used. Amongthe methods, a method for producing a liquid chemical preferablyincludes a filtration step of filtering a purification target substancecontaining an organic solvent using a filter to obtain a liquid chemicalfrom the viewpoint that then, a liquid chemical exhibiting moreexcellent effects of the present invention is obtained.

The purification target substance used in the filtration step isobtained by purchasing or the like, and by reacting raw materials. Asthe purification target substance, it is preferable to use theabove-described substance in which a content of particles and/orimpurities is small. Examples of commercially available products of suchpurification target substance include a product called “high-puritygrade product.”

A method of obtaining a purification target substance (typically, apurification target substance containing an organic solvent) by reactingraw materials is not particularly limited, and known methods can beused. For example, there is a method in which one or plural rawmaterials are reacted in the presence of a catalyst to obtain an organicsolvent.

More specific examples thereof include a method of reacting acetic acidand n-butanol in the presence of sulfuric acid to obtain butyl acetate;a method of reacting ethylene, oxygen, and water in the presence of Al(C₂H₅)₃ to obtain 1-hexanol; a method of reacting cis-4-methyl-2-pentenein the presence of Ipc2BH (Diisopinocampheylborane) to obtain4-methyl-2-pentanol; a method of reacting propylene oxide, methanol, andacetic acid in the presence of sulfuric acid to obtain PGMEA (propyleneglycol 1-monomethyl ether 2-acetate); a method of reacting acetone andhydrogen in the presence of copper oxide-zinc oxide-aluminum oxide toobtain IPA (isopropyl alcohol); a method of reacting lactic acid andethanol to obtain ethyl lactate; and the like.

Filtration Step

The method for producing a liquid chemical according to the embodimentof the present invention includes a filtration step of filtering theabove-mentioned purification target substance using a filter to obtain aliquid chemical. A method of filtering the purification target substanceusing a filter is not particularly limited, and it is preferable thatthe purification target substance be passed through (allowing a liquidto be passed through) a filter unit having a housing and a cartridgefilter housed in the housing under pressurization or non-pressurization.

Pore Diameter of Filter

A pore diameter of the filter is not particularly limited, and it ispossible to use filters having a pore diameter which are generally usedfor filtering a purification target substance. Among the filters, a porediameter of the filter is preferably 200 nm or smaller, more preferably20 nm or smaller, even more preferably 10 nm or smaller, particularlypreferably 5 nm or smaller, and most preferably 3 nm or smaller, fromthe viewpoint that then, it is possible to easily control the number ofparticles contained in the liquid chemical which have a particle size of0.5 to 17 nm within a desired range. The lower limit value is notparticularly limited, but in general, it is preferably 1 nm or largerfrom the viewpoint of productivity.

In the present specification, a pore diameter and pore diameterdistribution of the filter respectively refer to a pore diameter andpore diameter distribution determined by a bubble point of isopropanol(IPA) or HFE-7200 (“Novec 7200,” manufactured by 3M, hydrofluoroether,C₄F₉OC₂H₅).

In a case where a pore diameter of the filter is 5.0 nm or smaller, thisis preferable from the viewpoint that then, it is possible to easilycontrol the number of particles contained in the liquid chemical whichhave a particle size of 0.5 to 17 nm. Hereinafter, a filter having apore diameter of 5 nm or smaller is also referred to as a “microporediameter filter.”

The micropore diameter filter may be used alone or in combination with afilter having a different pore diameter. Among filters, it is preferableto use a filter having a larger pore diameter in combination from theviewpoint of more excellent productivity. In this case, a liquid of apurification target substance, which has been filtered through a filterhaving a larger pore diameter in advance, is passed through themicropore diameter filter, whereby clogging of the micropore diameterfilter can be prevented.

That is, as a pore diameter of the filter, in a case of using onefilter, a pore diameter of the filter is preferably 5.0 nm or smaller,and in a case of using two or more filters, the smallest pore diameteramong pore diameters of the filters is preferably 5.0 nm or smaller.

An aspect in which two or more kinds of filters having different porediameters are sequentially used is not particularly limited, andexamples thereof include a method of sequentially disposing theabove-described filter units along a pipe line through which apurification target substance is transferred. At this case, in a casewhere a flow rate of a purification target substance per unit time ismade constant in the entire pipe line, in some cases, a larger pressureis applied to a filter unit having a smaller pore diameter as comparedwith a filter unit having a larger pore diameter. In this case, it ispreferable to increase a filtration area by disposing a pressureadjustment valve, a damper, and the like between filter units, andthereby making a pressure applied to a filter unit having a small porediameter constant, or by disposing the filter units in which the samefilter is housed in parallel along the pipe line. Accordingly, it ispossible to more stably control the number of particles of 0.5 to 17 nmcontained in the liquid chemical.

Material of Filter

A material of the filter is not particularly limited, and knownmaterials for the filter can be used. Specific examples thereof in acase where a resin is used include polyamides such as 6-nylon and6,6-nylon; polyolefins such as polyethylene and polypropylene;polystyrene; polyimide; polyamide imide; poly(meth)acrylate;polyfluorocarbons such as polytetrafluoroethylene,perfluoroalkoxyalkane, perfluoroethylene propene copolymer,ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, polychlorotrifluoroethylene, polyvinylidenefluoride, and polyvinyl fluoride; polyvinyl alcohols; polyesters;celluloses; cellulose acetates; and the like. Among the examples, atleast one selected from the group consisting of nylon (among which6,6-nylon is preferable), polyolefins (among which polyethylene ispreferable), poly(meth)acrylates, and polyfluorocarbons (among whichpolytetrafluoroethylene (PTFE) and perfluoroalkoxyalkane (PFA) arepreferable) is preferable from the viewpoint that then, a filter hasmore excellent solvent resistance, and a liquid chemical to be obtainedexhibits more excellent defect inhibitive performance. As thesepolymers, one kind thereof can be used alone or two or more kindsthereof can be used in combination.

Furthermore, in addition to the resin, diatomaceous earth, glass, andthe like may be used.

In addition, the filter may be surface-treated. A method of surfacetreatment is not particularly limited, and known methods can be used.Examples of a method of surface treatment include a chemicalmodification treatment, a plasma treatment, a hydrophobic treatment,coating, a gas treatment, sintering, and the like.

A plasma treatment is preferable because then a surface of the filter ishydrophilized. A water contact angle on a surface of the filter that hasbeen hydrophilized by a plasma treatment is not particularly limited,but a static contact angle at 25° C. measured by a contact angle meteris preferably 60° or less, more preferably 50° or less, and even morepreferably 30° or less.

As a chemical modification treatment, a method of introducing an ionexchange group into a base material of the filter is preferable.

That is, as the filter, a filter in which each of the above-describedmaterials is used as a base material and an ion exchange group isintroduced into the base material is preferable. Typically, a filterincluding a base material having an ion exchange group on a surface ofthe base material is preferable. A surface-modified base material is notparticularly limited, and a base material in which an ion exchange groupis introduced into the above-mentioned polymer is preferable from theviewpoint that then, production becomes easier.

Regarding an ion exchange group, examples of cation exchange groupsinclude a sulfonic acid group, a carboxy group, a phosphoric acid group,and the like, and examples of anion exchange groups include a quaternaryammonium group and the like. A method of introducing an ion exchangegroup into a polymer is not particularly limited, and examples thereofinclude a method of reacting a compound having an ion exchange group anda polymerizable group with a polymer for typically grafting.

A method of introducing an ion exchange group is not particularlylimited, but fibers of the above-mentioned resin are irradiated withionizing radiation (such as α-rays, β-rays, γ-rays, X-rays, electronrays, and the like) to generate active portions (radicals) in the resin.This irradiated resin is immersed in a monomer-containing solution tograft-polymerize the monomer onto a base material. As a result, apolymer in which this monomer is bonded to polyolefin fibers as agraft-polymerized side chain is generated. By contacting and reacting aresin having this generated polymer as a side chain with a compoundhaving an anion exchange group or a cation exchange group, an ionexchange group is introduced into the polymer of the graft-polymerizedside chain, and thereby a final product is obtained.

In addition, the filter may have a configuration in which a woven or anon-woven fabric in which an ion exchange group is formed by a radiationgraft polymerization method is combined with a glass wool, a woven, or anon-woven fabric of the related art.

In a case where a filter having an ion exchange group is used, it iseasy to control a content of particles containing a metal atom in theliquid chemical within a desired range. A material of the filter havingan ion exchange group is not particularly limited, and examples thereofinclude a material in which an ion exchange group has been introducedinto polyfluorocarbon or polyolefin, and a material in which an ionexchange group has been introduced into polyfluorocarbon is morepreferable.

A pore diameter of the filter having an ion exchange group is notparticularly limited, but it is preferably 1 to 30 nm and morepreferably 5 to 20 nm. The filter having an ion exchange group may alsoserve as the above-mentioned filter having the smallest pore diameter,or may be used separately from the filter having the smallest porediameter. Among the examples, as the filtration step, an aspect ispreferable in which a filter having an ion exchange group is used incombination with a filter not having an ion exchange group and havingthe smallest pore diameter, from the viewpoint that then, it is possibleto obtain a liquid chemical exhibiting more excellent effects of thepresent invention.

A material of the above-described filter having the smallest porediameter is not particularly limited, but in general, at least oneselected from the group consisting of polyfluorocarbons and polyolefinsis preferable, and polyolefin is more preferable from the viewpoint ofsolvent resistance and the like.

In addition, in a case where a material of the filter is polyamide(particularly, nylon), it is possible to more easily control a contentof a high-boiling point organic compound and the particles U in theliquid chemical, and in particular, it is possible to further moreeasily control a content of the particles U in the liquid chemical.

Accordingly, as the filter used in the filtration step, it is preferableto use two or more kinds of filters of different materials, and it ismore preferable to use two or more kinds thereof selected from the groupconsisting of polyolefins, polyfluorocarbons, polyamides, and a basematerial in which an ion exchange group has been introduced in thesematerials.

Pore Structure of Filter

A pore structure of the filter is not particularly limited, and it maybe appropriately selected according to components in a purificationtarget substance. In the present specification, a pore structure of afilter means pore diameter distribution, positional distribution ofpores in a filter, a shape of pores, and the like, and it can betypically controlled by a method for manufacturing a filter.

For example, in a case where a filter is formed by sintering a powder ofa resin or the like, a porous film can be obtained, and in a case wherea filter is formed by a method such as electrospinning, electroblowing,and melt-blowing, a fiber film can be obtained. These filtersrespectively have different pore structures.

A “porous film” refers to a film allowing components in a purificationtarget substance such as gels, particles, colloids, cells, and oligomersto be retained, and allowing components that are substantially smallerthan pores to be passed through the pores. The retention of componentsin a purification target substance by the porous film may depend inoperating conditions such as a surface velocity, use of surfactants, apH, and a combination thereof, and may depend on a pore diameter andstructure of the porous film, and a size and structure (whetherparticles are hard particles, gels, or the like) of particles to beremoved.

In a case where a purification target substance contains the particles U(which may be in a gel form) as impurities, particles containing ahigh-boiling point organic compound are negatively charged in manycases, and a filter made of polyamide performs a function of a non-sievefilm for removing such particles. Typical examples of non-sieve filmsinclude nylon films such as nylon-6 films and nylon-6,6 films, butexamples are not limited thereto.

The “non-sieving” retention mechanism referred to in the presentspecification refers to retention by mechanisms, such as obstruction,diffusion, and adsorption, which are not related to filter pressure dropor pore diameters.

The non-sieving retention includes retention mechanisms, such asobstruction, diffusion, and adsorption, which remove removal targetparticles from a purification target substance, and which are notrelated to filter pressure drop or filter pore diameters. The adsorptionof particles on a filter surface can be mediated by, for example,intermolecular Van der Waals forces, electrostatic forces, or the like.An obstructive effect occurs in a case where particles traveling in anon-sieving film layer having a tortuous path cannot change theirdirection quickly enough to avoid coming into contact with thenon-sieving film. Particle transport by diffusion mainly occurs fromrandom motion or Brownian motion of small particles, which creates acertain probability that the particles will collide with a filtrationmaterial. The non-sieving retention mechanism becomes active in a casewhere no repulsion force is present between particles and a filter.

Ultra high molecular weight polyethylene (UPE) filters are typicallysieve films. A sieve film refers to a film that mainly capturesparticles by a sieving retention mechanism, or a film that is optimizedfor capturing particles by a sieving retention mechanism.

Typical examples of sieve films include polytetrafluoroethylene (PTFE)films and UPE films, but examples are not limited thereto.

The “sieving retention mechanism” refers to retention resulted due toremoval target particles being larger than a pore diameter of a porousfilm. A sieving retention force can be improved by formation of a filtercake (aggregation of removal target particles on a film surface). Thefilter cake effectively performs a function of a secondary filter.

A material of a fiber layer is not particularly limited as long as it isa polymer from which a fiber layer can be formed. Examples of polymersinclude polyamide and the like. Examples of polyamides include nylon 6,nylon 6,6, and the like. The polymer for forming a fiber film may bepoly(ethersulfone). In a case where a fiber film is on a primary side ofa porous film, surface energy of the fiber film is preferably higherthan that of a polymer that is a material of the porous film and is on asecondary side. Examples of such combinations include a case in which amaterial of the fiber film is nylon and a porous film is polyethylene(UPE).

A method for producing a fiber film is not particularly limited, andknowns method can be used. Examples of methods for producing a fiberfilm include electrospinning, electroblowing, melt-blowing, and thelike.

A pore structure of a porous film (for example, porous films includingUPE, PTFE, and the like) is not particularly limited, and examples ofpore shapes include a lace shape, a string shape, a node shape, and thelike.

Pore diameter distribution in a porous film and position distribution inthe film are not particularly limited. The size distribution may besmaller and the position distribution in the film may be symmetric.Alternatively, the size distribution may be larger and the positiondistribution in the film may be asymmetric (the above film is alsoreferred to as an “asymmetric porous film”). In the asymmetric porousfilm, a size of pores varies throughout the film, and typically, a porediameter increases from one surface of the film toward the other surfaceof the film. In this case, a surface on a side with many pores having alarge pore diameter is referred to as an “open side”, and a surface on aside with many pores with a small pore diameter is referred to as a“tight side.”

In addition, examples of asymmetric porous films include a film (whichis also referred to as a “hourglass shape”) in which a size of pores isa minimum at a certain position in a thickness of the film.

In a case where an asymmetric porous film is used and pores having alarger size are on a primary side, in other words, in a case where aprimary side is an open side, a pre-filtration effect can be produced.

The porous film may contain thermoplastic polymers such as PESU(polyethersulfone), PFA (perfluoroalkoxyalkane, a copolymer of ethylenetetrafluoride and perfluoroalkoxyalkane), polyamide, and polyolefin, ormay contain polytetrafluoroethylene and the like.

Among the examples, an ultra high molecular weight polyethylene ispreferable as a material of the porous film. An ultra high molecularweight polyethylene refers to a thermoplastic polyethylene having anextremely long chain, and preferably has a molecular weight of 1,000,000or more, typically 2,000,000 to 6,000,000.

As the filter used in the filtration step, it is preferable to use twoor more kinds of filters having different pore structures, and it ismore preferable to use a filter of a porous film and a fiber film.Specifically, it is preferable to use a filter of a nylon fiber film anda filter of a UPE porous film in combination.

As described above, the filtration step according to the embodiment ofthe present invention is preferably a multi-stage filtration step inwhich a purification target substance is passed through two or morekinds of filters different in at least one selected from the groupconsisting of a filter material, a pore diameter, and a pore structure.

Multi-Stage Filtration Step

The multi-stage filtration step can be performed using knownpurification devices. FIG. 1 is a schematic diagram showing a typicalexample of a purification device with which the multi-stage filtrationstep can be performed. A purification device 10 includes a productiontank 11, a filtration device 16, and a filling device 13, and therespective units are connected by a pipe line 14.

The filtration device 16 has filter units 12(a) and 12(b) connected bythe pipe line 14. An adjustment valve 15(a) is disposed in the pipe linebetween the filter units 12(a) and 12(b).

FIG. 1 shows a case in which the number of filter units is two, butthree or more filter units may be used.

In FIG. 1, a purification target substance is stored in the productiontank 11. Next, a pump (not shown) disposed in the pipe line 14 isoperated, and the purification target substance is sent from theproduction tank 11 to the filtration device 16 via the pipe line 14. Adirection in which the purification target substance is transferred inthe purification device 10 is indicated by F₁ in FIG. 1.

The filtration device 16 consists of the filter units 12(a) and 12(b)connected by the pipe line 14. In each of the two filter units, acartridge filter, which has filters different in at least one selectedfrom the group consisting of a pore diameter, a material, and a porestructure, is housed. The filtration device 16 has a function offiltering a purification target substance supplied through a pipe lineby a filter.

The filter housed in the respective filter units is not particularlylimited, but a filter having the smallest pore diameter is preferablyhoused in the filter unit 12(b).

By operating the pump, the purification target substance is supplied tothe filter unit 12(a) to be filtered. The purification target substancefiltered by the filter unit 12(a) is reduced in pressure as needed bythe adjustment valve 15(a), and supplied to the filter unit 12(b) to befiltered.

The purification device may not include the adjustment valve 15(a). Inaddition, even in a case where the purification device includes theadjustment valve 15(a), a position thereof may be on a primary side ofthe filter unit 12(a).

Furthermore, as a device capable of adjusting a supply pressure for apurification target substance, a device other than the adjustment valvemay be used. Examples of such a member include a damper and the like.

In addition, in the filtration device 16, each filter forms a cartridgefilter, but a filter that can be used in the purification methodaccording to the present embodiment is not limited to theabove-described embodiment. For example, an aspect in which apurification target substance is passed through a filter formed in aflat plate shape may be employed.

Furthermore, a configuration is employed in which, in the purificationdevice 10, a purification target substance that has been filtered by thefilter unit 12(b) is transferred to the filling device 13 andaccommodated in a container. However, the filtration device forperforming the above-described purification method is not limited to theabove configuration, and a configuration may be employed in which apurification target substance that has been filtered by the filter unit12(b) is returned to the production tank 11, and a liquid thereof isagain passed through the filter unit 12(a) and the filter unit 12(b).The above-mentioned filtration method is called circulation filtration.In purification of a purification target substance by the circulationfiltration, at least one of two or more kinds of filters is used twiceor more. In the present specification, an operation of returning afiltered purification target substance, which has been filtered by therespective filter units, again to the production tank is counted as onecirculation. The number of circulations may be appropriately selectedaccording to components in a purification target substance, and thelike.

A material of a liquid-contacting part (referring to an inner wallsurface or the like with which a purification target substance and theliquid chemical may come into contact) of the above-mentionedpurification device is not particularly limited, but theliquid-contacting part is preferably formed of at least one kind(hereinafter, also collectively referred to as a “corrosion-resistantmaterial”) selected from the group consisting of a non-metallic materialand an electrolytically polished metallic material. For example, in acase where the liquid-contacting part of the production tank is formedof a corrosion-resistant material, this means there are cases in whichthe production tank itself consists of a corrosion-resistant material,or an inner wall or the like of the production tank is coated with acorrosion-resistant material.

The above-mentioned non-metallic material is not particularly limited,and known materials can be used.

Examples of non-metallic materials include at least one selected fromthe group consisting of a polyethylene resin, a polypropylene resin, apolyethylene-polypropylene resin, a tetrafluoroethylene resin, atetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, atetrafluoroethylene-hexafluoropropylene copolymer resin, atetrafluoroethylene-ethylene copolymer resin, atrifluorochloroethylene-ethylene copolymer resin, a fluorovinylideneresin, a trifluorochloroethylene copolymer resin, and a fluorovinylresin, but examples are not limited thereto.

The above-mentioned metallic material is not particularly limited, andknown materials can be used.

Examples of metallic materials include metallic materials in which atotal content of Cr and Ni is more than 25% by mass with respect to atotal mass of the metallic material, and among the metallic materials, ametallic material in which a total content of chromium and nickel is 30%by mass or more with respect to a total mass of the metallic material ismore preferable. The upper limit value of a total content of Cr and Niin the metallic material is not particularly limited, but in general, itis preferably 90% by mass or less.

Examples of metallic materials include stainless steel, a Ni—Cr alloy,and the like.

The stainless steel is not particularly limited, and known stainlesssteels can be used. Among the steels, an alloy containing Ni at 8% bymass or more is preferable, and an austenitic stainless steel containingNi at 8% by mass or more is more preferable. Examples of austeniticstainless steels include SUS (Steel Use Stainless) 304 (Ni content: 8%by mass, Cr content: 18% by mass), SUS304L (Ni content: 9% by mass, Crcontent: 18% by mass), SUS316 (Ni content: 10% by mass, Cr content: 16%by mass), SUS316L (Ni content: 12% by mass, Cr content: 16% by mass),and the like.

The Ni—Cr alloy is not particularly limited, and known Ni—Cr alloys canbe used. Among the Ni—Cr alloys, a Ni—Cr alloy having a Ni content of40% to 75% by mass and a Cr content of 1% to 30% by mass is preferable.

Examples of Ni—Cr alloys include HASTELLOY (trade name, the same applieshereinafter), MONEL (trade name, the same applies hereinafter), INCONEL(trade name, hereinafter the same), and the like. More specific examplesthereof include HASTELLOY C-276 (Ni content: 63% by mass, Cr content:16% by mass), HASTELLOY C (Ni content: 60% by mass, Cr content: 17% bymass), HASTELLOY C-22 (Ni content: 61% by mass, Cr content: 22% bymass), and the like.

In addition, the Ni—Cr alloy may further contain B, Si, W, Mo, Cu, Co,and the like if necessary, in addition to the above alloys.

A method of electrolytically polishing a metallic material is notparticularly limited, and known methods can be used. For example, it ispossible to use methods described in paragraphs 0011 to 0014 ofJP2015-227501A, paragraphs 0036 to 0042 of JP2008-264929A, and the like.

In a case where the metallic material is electrolytically polished, itis presumed that a content of Cr in a passivation layer on a surfacebecomes larger than a content of Cr in a primary phase. Accordingly, ina case of using a purification device in which a liquid-contacting partis formed of a metallic material that has been electrolyticallypolished, it is presumed that metal impurities containing metal atoms ina purification target substance are unlikely to flow out.

The metallic material may be buff-polished. A method of buff polishingis not particularly limited, and known methods can be used. A size ofabrasive grains for polishing used for buff polishing finish is notparticularly limited, but it is preferably #400 or less from theviewpoint that then unevenness of a surface of the metallic material iseasily reduced. The buff polishing is preferably performed before theelectrolytic polishing.

Other Steps

The method for producing a liquid chemical according to the embodimentof the present invention is not particularly limited as long as it hasthe filtration step, and the method may further include steps other thanthe filtration step. Examples of steps other than the filtration stepinclude a distillation step, a reaction step, a static electricityremoval step, and the like.

Distillation Step

The distillation step is a step of distilling a purification targetsubstance containing an organic solvent to obtain a distilledpurification target substance. A method of distilling a purificationtarget substance is not particularly limited, and known methods can beused. Typical examples thereof include a method in which a distillationcolumn is disposed on a primary side of the above-described purificationdevice, and a distilled purification target substance is introduced intoa production tank.

In this case, a liquid-contacting part of the distillation column is notparticularly limited, but it is preferably formed of the above-describedcorrosion-resistant material.

Reaction Step

The reaction step is a step of reacting raw materials to generate apurification target substance containing an organic solvent as areactant. A method of generating a purification target substance is notparticularly limited, and known methods can be used. Typical examplesthereof include a method in which a reactor is disposed on a primaryside of the production tank (or the distillation column) of thepurification device described above, and the reactant is introduced intothe production tank (or the distillation column).

In this case, a liquid-contacting part of the reactor is notparticularly limited, but it is preferably formed of the above-describedcorrosion-resistant material.

Static Electricity Removal Step

The static electricity removal step is a step of reducing chargepotential of the purification target substance by removing staticelectricity of the purification target substance.

A method of static electricity removal is not particularly limited, andknown static electricity removal methods can be used. Examples ofmethods of static electricity removal include a method of bringing apurification target substance into contact with a conductive material.

A contact time for bringing a purification target substance into contactwith a conductive material is preferably 0.001 to 60 seconds, morepreferably 0.001 to 1 second, and even more preferably 0.01 to 0.1seconds. Examples of conductive materials include stainless steel, gold,platinum, diamond, glassy carbon, and the like.

Examples of methods of bringing a purification target substance intocontact with a conductive material include a method in which a groundedmesh consisting of a conductive material is disposed inside a pipe line,and a purification target substance is passed therethrough.

In purification of a purification target substance, opening of acontainer, cleaning of the container and the devices, accommodation of asolution, analysis, and the like, which are accompanying procedures ofthe purification, are all preferably performed in a clean room. Theclean room is preferably a clean room having a cleanliness of 4 orhigher which is specified by International Standard ISO 14644-1: 2015specified by the International Organization for Standardization.Specifically, the clean room preferably satisfies any of ISO class 1,ISO class 2, ISO class 3, and ISO class 4; more preferably satisfies ISOclass 1 or ISO class 2; and even more preferably satisfies ISO class 1.

A storage temperature for the liquid chemical is not particularlylimited, but the storage temperature is preferably 4° C. or higher fromthe viewpoint that then, a trace amount of impurities and the likecontained in the liquid chemical are less likely to be eluted, and as aresult, more excellent effects of the present invention are obtained.

Liquid-Chemical-Accommodating Body

The liquid chemical produced by the above-described purification methodmay be accommodated in a container to be stored therein until used.

Such a container, and a liquid chemical (or a resist composition)accommodated in the container are collectively referred to as aliquid-chemical-accommodating body. The liquid chemical is taken outfrom a stored-liquid-chemical-accommodating body and used.

As a container for storing the liquid chemical, a container, in which adegree of cleanliness of an inner side is high and elution of impuritiesoccurs less, is preferable in consideration of a use application formanufacturing semiconductor devices.

Specific examples of usable containers include “CLEAN Bottle” seriesmanufactured by AICELLO CORPORATION, “Pure Bottle” manufactured byKODAMA PLASTICS Co., Ltd., and the like, but examples are not limitedthereto.

As the container, it is preferable to use a multi-layer bottle in whicha container inner wall has a six-layer structure made of six kinds ofresins, or a multi-layer bottle in which a container inner wall has aseven-layer structure made of seven kinds of resins for the purpose ofpreventing impurities from being mixed (contamination) into the liquidchemical. Examples of these containers include a container described inJP2015-123351A.

A liquid-contacting part of this container preferably consists of theabove-described corrosion-resistant material, or glass. It is preferablethat 90% or more of an area of the liquid-contacting part consists ofthe above-mentioned material, and it is more preferable that the entireliquid-contacting part consists of the above-mentioned material from theviewpoint that then, more excellent effects of the present invention areobtained.

EXAMPLES

Hereinafter, the present invention will be described in more detailbased on examples. In the following examples, materials, amounts thereofused, ratios thereof, the details of treatments, treatment procedures,and the like can be suitably modified without departing from the scopeof the present invention. Accordingly, the scope of the presentinvention should not be limitedly interpreted by the following examples.

In preparation of liquid chemicals of examples and comparative examples,handling of containers, preparation of liquid chemicals, filling,storage, and analytical measurement were all performed in a clean roomhaving a level satisfying ISO class 2 or 1. In measurement of contentsof organic impurities, and measurement of contents of metal atoms, in acase of measuring a liquid chemical below a detection limit in normalmeasurement, the measurement was performed after concentrating theliquid chemical to 1/100 in terms of volume, and a content thereof wascalculated by converting the concentration to a concentration of asolution before performing the concentration to improve measurementaccuracy. Devices used for purification and instruments such as a filterand a container were used after their liquid-chemical-contactingsurfaces were sufficiently cleaned with a liquid chemical that had beenpurified by the same method.

Purification of Liquid Chemical 1

A liquid chemical was produced by performing filtration using the samepurification device as that shown in FIG. 1 except that a purificationtarget substance (a commercial product) containing cyclohexanone (CHN)as an organic solvent was prepared, five filter units were disposed inseries with respect to a pipe line, a filtration device not having anadjustment valve was used, and a pipe line, which can return a filteredpurification target substance to a production tank after filtration by afilter unit at the most downstream side, was used. The following filterswere disposed in the respective filter units from a primary side (inTable 1, the filters are respectively described as first to fifthfilters).

-   -   Polypropylene filter (pore diameter: 200 nm, a porous film,        described as “PP” in the table)    -   Polyfluorocarbon filter having an ion exchange group (pore        diameter: 20 nm, a fiber film of a polymer of PTFE and PES        (polyethylene sulfonic acid), described as “IEX” in the table)    -   IEX filter having a pore diameter 5 nm    -   Nylon filter (pore diameter: 10 nm, a fiber film, described as        “Nylon” in the table)    -   UPE filter (pore diameter: 3 nm, a porous film, described as        “UPE” in the table)

A purification target substance that had passed through the above fivefilter units was returned to the production tank. This operation wasrepeated three times, and thereby a liquid chemical was obtained.

Purification of Liquid Chemicals 2 to 25

Liquid chemicals 2 to 25 were obtained by purifying a purificationtarget substance containing an organic solvent shown in Table 1 underconditions shown in Table 1. The respective liquid chemicals wereobtained as follows: a liquid of a purification target substance waspassed through each of the filters shown in Table 1 from the firstfilter to the fifth filter in order (where a liquid chemical with ablank filter column indicates that the filter was not used, for example,in the case of the liquid chemical 24, a liquid passed through the firstfilter to the third filter); and this operation was repeated for thenumber of times shown in the section of “Number of circulations.”

As purification target substances shown in Table 1, purification targetsubstances respectively having different lots were obtained.Accordingly, components other than an organic solvent initiallycontained in the respective purification target substances may bedifferent in some cases.

Abbreviations in Table 1 respectively represent the following contents.

-   -   PGMEA/PGME (7:3): a mixed solution of PGMEA and PGME mixed at        7:3 (v/v)    -   NBA: n-butyl acetate    -   IAA: isoamyl acetate    -   MIBC: methyl isobutyl carbinol    -   IPA: isopropanol    -   PC/PGMEA (1:9): a mixed solution of PC and PGMEA mixed at 1:9        (v/v)    -   EL: ethyl lactate    -   IEX: an IEX filter having a pore diameter of 10 nm    -   PTFE: a polytetrafluoroethylene filter (porous film)    -   UPE: an ultra high molecular weight polyethylene filter (which        is a porous film)

TABLE 1 First filter Second filter Third filter Fourth filter Fifthfilter Purification target Pore Pore Pore Pore Pore substance diameterdiameter diameter diameter diameter Number of Table 1 Organic solventMaterial (nm) Material (nm) Material (nm) Material (nm) Material (nm)circulations Liquid CHN PP 200 IEX 20 IEX 5 Nylon 10 UPE 3 3 chemical 1Liquid CHN PP 200 IEX 20 IEX 10 Nylon 10 UPE 3 3 chemical 2 Liquid CHNPP 200 IEX 20 IEX 20 Nylon 10 UPE 3 3 chemical 3 Liquid CHN PP 200 IEX20 IEX 20 Nylon 10 UPE 3 1 chemical 4 Liquid CHN PP 200 IEX 5 IEX 5Nylon 10 UPE 3 3 chemical 5 Liquid CHN PP 200 IEX 10 IEX 10 Nylon 10 UPE3 3 chemical 6 Liquid CHN PP 200 IEX 20 IEX 20 Nylon 10 UPE 5 3 chemical7 Liquid CHN PP 200 IEX 5 IEX 5 Nylon 10 UPE 3 10 chemical 8 Liquid CHNPP 200 IEX 10 IEX 10 Nylon 10 UPE 3 5 chemical 9 Liquid CHN PP 200 IEX20 IEX 10 Nylon 10 UPE 3 3 chemical 10 Liquid CHN PP 200 IEX 20 IEX 20PTFE 20 UPE 3 3 chemical 11 Liquid CHN PP 200 IEX 20 IEX 20 PTFE 10 UPE3 3 chemical 12 Liquid CHN PP 200 IEX 20 IEX 20 PTFE 10 UPE 5 3 chemical13 Liquid CHN PP 200 IEX 20 IEX 20 PTFE 10 UPE 3 2 chemical 14 LiquidCHN PP 200 IEX 20 IEX 20 PTFE 10 PTFE 5 3 chemical 15 Liquid PGMEA/ PP200 IEX 20 IEX 5 Nylon 10 UPE 3 3 chemical 16 PGME(7:3) Liquid nBA PP200 IEX 20 IEX 5 Nylon 10 UPE 3 3 chemical 17 Liquid PC/ PP 200 IEX 20IEX 5 Nylon 10 UPE 3 3 chemical 18 PGMEA(1:9) Liquid PGMEA PP 200 IEX 20IEX 5 Nylon 10 UPE 3 3 chemical 19 Liquid EL PP 200 IEX 20 IEX 5 Nylon10 UPE 3 3 chemical 20 Liquid iAA PP 200 IEX 20 IEX 5 Nylon 10 UPE 3 3chemical 21 Liquid MIBC PP 200 IEX 20 IEX 5 Nylon 10 UPE 3 3 chemical 22Liquid IPA PP 200 IEX 20 IEX 5 Nylon 10 UPE 3 3 chemical 23 Liquid CHNPP 200 IEX 10 PTFE 10 1 chemical 24 Liquid CHN PP 200 IEX 10 IEX 10 IEX10 chemical 25 Evaluation of number of particles contained which haveparticle size of 0.5 to 17 nm in liquid chemical

A content (the number of particles contained) of particles having aparticle size of 0.5 to 17 nm in the liquid chemical was measured by thefollowing method.

First, a predetermined amount of a liquid chemical was applied on asilicon substrate to form a substrate having a liquid chemical layer,and a surface of the substrate having a liquid chemical layer wasscanned with laser light to detect scattering light. Thereby, a positionand a particle size of a defect present on the surface of the substratehaving a liquid chemical layer were specified. Next, based on theposition of the defect, elemental analysis was performed by an EDX(energy dispersive X-ray) analysis method to examine a composition ofthe defect. By this method, the number of Fe nanoparticles, Pbnanoparticles, Cr nanoparticles, and Ti nanoparticles on the substratewas obtained and converted into the number of particles contained perunit volume of the liquid chemical (particles/cm³).

Furthermore, in the same manner, a composition of the Fe nanoparticles(a simple substance of Fe, and an oxide of a Fe atom), an associationstate with a high-boiling point organic compound, and the like were alsoidentified.

For pattern analysis, a wafer inspection system “SP-5” manufactured byKLA-Tencor was used in combination with a fully automatic defect reviewand classification device “SEMVision G6” of Applied Materials, Inc.

A sample, for which particles having a desired particle size could notbe detected due to circumstances such as a resolution capability of themeasuring device, was detected using a method described in paragraphs0015 to 0067 of JP2009-188333A. That is, an SiO_(x) layer was formed ona substrate by a chemical vapor deposition (CVD) method, and next, aliquid chemical layer was formed to cover this layer. Next, a method wasused in which a composite layer having the SiO_(x) layer and the liquidchemical layer applied thereon was dry-etched, the obtained protrudingobject was irradiated with light to detect scattering light, a volume ofthe protruding object was calculated from the scattering light, and aparticle size of the particles was calculated from the volume of theprotruding object.

Table 2 shows the measurement results for the respective liquidchemicals, a ratio of the number of particles contained which wascalculated based on the measurement results, and the like.

TABLE 2 Configuration of metal nanoparticles Table 2 Organic Fenanoparticles Pb nanoparticles Cr nanoparticles Ti nanoparticles(part 1) solvent (particles/cm³) (particles/cm³) (particles/cm³)(particles/cm³) Fe/Pb Fe/Cr Liquid CHN 1.2 ×10⁵ 9.0 × 10² 1.5 × 10³ 3.0× 10³ 1.3 × 10² 8.0 × 10¹ chemical 1 Liquid CHN 1.5 × 10⁵ 5.8 × 10³ 4.8× 10³ 6.0 × 10³ 2.6 × 10¹ 3.1 × 10¹ chemical 2 Liquid CHN 1.6 × 10⁵ 4.6× 10⁴ 2.3 × 10⁴ 4.1 × 10⁴ 3.5 × 10⁰ 7.0 × 10⁰ chemical 3 Liquid CHN 1.3× 10⁵ 9.0 × 10⁴ 4.6 × 10⁴ 6.5 × 10⁴ 1.4 × 10⁰ 2.8 × 10⁶ chemical 4Liquid CHN 1.5 × 10⁵ 6.0 × 10¹ 1.4 × 10¹ 1.0 × 10² 2.5 × 10³ 1.1 × 10⁴chemical 5 Liquid CHN 1.4 × 10⁵ 1.2 × 10⁴ 1.2 × 10⁴ 2.0 × 10⁴ 1.2 × 10¹1.2 × 10¹ chemical 6 Liquid CHN 1.5 × 10⁵ 8.0 × 10⁴ 1.7 × 10⁵ 3.5 × 10⁴1.9 × 10⁰ 8.7 × 10¹ chemical 7 Liquid CHN 1.3 × 10⁵ 6.5 × 10¹ 8.5 × 10¹9.0 × 10⁰ 2.0 × 10³ 1.5 × 10³ chemical 8 Liquid CHN 1.9 × 10⁵ 8.0 × 10³5.8 × 10³ 1.7 × 10⁴ 2.4 × 10¹ 3.3 × 10¹ chemical 9 Liquid CHN 1.8 × 10⁵7.0 × 10⁴ 5.0 × 10³ 2.0 × 10⁵ 2.6 × 10⁰ 3.6 × 10¹ chemical 10 Liquid CHN2.1 × 10⁴ 1.2 × 10³ 2.0 × 10³ 3.9 × 10³ 1.8 × 10¹ 1.1 × 10¹ chemical 11Liquid CHN 4.2 × 10⁴ 7.5 × 10³ 6.2 × 10³ 7.8 × 10³ 5.6 × 10⁶ 6.7 × 10⁰chemical 12 Liquid CHN 1.6 × 10⁴ 1.3 × 10³ 1.1 × 10³ 2.6 × 10³ 1.2 × 10¹1.4 × 10¹ chemical 13 Liquid CHN 1.6 × 10⁴ 1.6 × 10³ 1.8 × 10³ 3.1 × 10³1.0 × 10¹ 8.9 × 10⁰ chemical 14 Liquid CHN 1.5 × 10⁴ 1.8 × 10³ 9.5 × 10²1.9 × 10³ 8.3 × 10⁰ 1.6 × 10¹ chemical 15 Liquid PGMEA/ 1.1 × 10⁴ 6.0 ×10² 5.2 × 10² 1.5 × 10³ 1.8 × 10¹ 2.1 × 10¹ chemical 16 PGME (7:3)Liquid nBA 1.2 × 10⁴ 8.0 × 10² 4.0 × 10² 1.8 × 10³ 1.5 × 10¹ 3.0 × 10¹chemical 17 Liquid PC/ 1.6 × 10⁴ 1.1 × 10³ 8.9 × 10² 2.3 × 10³ 1.5 × 10¹1.8 × 10¹ chemical 18 PGMEA (1:9) Liquid PGMEA 1.7 × 10⁴ 1.0 × 10³ 9.0 ×10² 2.2 × 10³ 1.7 × 10¹ 1.9 × 10¹ chemical 19 Liquid EL 1.8 × 10⁴ 9.0 ×10² 8.8 × 10² 2.1 × 10³ 2.0 × 10¹ 2.0 × 10¹ chemical 20 Liquid iAA 1.9 ×10⁴ 8.5 × 10² 8.7 × 10² 2.5 × 10³ 2.2 × 10¹ 2.2 × 10¹ chemical 21 LiquidMIBC 1.5 × 10⁴ 1.2 × 10³ 8.6 × 10² 2.1 × 10³ 1.3 × 10¹ 1.7 × 10¹chemical 22 Liquid IPA 1.4 × 10⁴ 1.3 × 10³ 9.1 × 10² 2.2 × 10³ 1.1 × 10¹1.5 × 10¹ chemical 23 Liquid CHN 1.5 × 10⁷ 9.0 × 10¹ 5.0 × 10¹ 1.4 × 10²1.7 × 10⁵ 3.0 × 10⁵ chemical 24 Liquid CHN 1.2 × 10⁶ 1.3 × 10⁶ 4.3 × 10¹1.8 × 10² 9.2 × 10⁻¹ 2.8 × 10⁴ chemical 25

TABLE 3 Classification 1 of Fe nanoparticles Total of particlesClassification 2 of Fe nanoparticles Configuration of Particles A B andparticles C Particles U Particles V Table 2 metal nanoparticles (thenumber of (the number of High-boiling point (the number of (the numberof (part 2) Fe/Ti particles %) particles %) A/(B + C) organic compoundparticles %) particles %) U/V Liquid 4.0 × 10¹ 3 97 3.1 × 10⁻² Contained95 5 1.9 × 10¹ chemical 1 Liquid 2.5 × 10¹ 2 98 2.0 × 10⁻² Contained 937 1.3 × 10¹ chemical 2 Liquid 3.9 × 10⁰ 2 98 2.0 × 10⁻² Contained 95 51.9 × 10¹ chemical 3 Liquid 2.0 × 10⁰ 4 96 4.2 × 10⁻² Contained 97 3 3.2× 10¹ chemical 4 Liquid 1.5 × 10³ 2 98 2.0 × 10⁻² Contained 95 5 1.9 ×10¹ chemical 5 Liquid 7.0 × 10⁰ 3 97 3.1 × 10⁻² Contained 95 5 1.9 × 10¹chemical 6 Liquid 4.3 × 10⁰ 4 96 4.2 × 10⁻² Contained 95 5 1.9 × 10¹chemical 7 Liquid 1.4 × 10⁰ 3 97 3.1 × 10⁻² Contained 95 5 1.9 × 10¹chemical 8 Liquid 1.1 × 10¹ 2 98 2.0 × 10⁻² Contained 95 5 1.9 × 10¹chemical 9 Liquid  9.0 × 10⁻¹ 3 97 3.1 × 10⁻² Contained 96 4 2.4 × 10¹chemical 10 Liquid 5.4 × 10⁰ 59 41 1.4 × 10⁰  Contained 96 4 2.4 × 10¹chemical 11 Liquid 5.4 × 10⁰ 11 89 1.2 × 10⁻¹ Contained 93 7 1.3 × 10¹chemical 12 Liquid 6.0 × 10⁰ 2 98 2.0 × 10⁻² Contained 91 9 1.0 × 10¹chemical 13 Liquid 5.2 × 10⁰ 3 97 3.1 × 10⁻² Contained 99 1 9.9 × 10¹chemical 14 Liquid 7.9 × 10⁰ 2 98 2.0 × 10⁻² Contained 90 10  9.0 × 10⁰chemical 15 Liquid 7.3 × 10⁰ 2 98 2.0 × 10⁻² Contained 96 4 2.4 × 10¹chemical 16 Liquid 6.9 × 10⁰ 1 99 1.0 × 10⁻² Contained 91 9 1.0 × 10¹chemical 17 Liquid 7.0 × 10⁰ 1 99 1.0 × 10⁻² Contained 93 7 1.3 × 10¹chemical 18 Liquid 7.7 × 10⁰ 1 99 1.0 × 10⁻² Contained 92 8 1.2 × 10¹chemical 19 Liquid 8.6 × 10⁰ 2 98 2.0 × 10⁻² Contained 91 9 1.0 × 10¹chemical 20 Liquid 7.6 × 10⁰ 3 97 3.1 × 10⁻² Contained 91 9 1.0 × 10¹chemical 21 Liquid 7.1 × 10⁰ 2 98 2.0 × 10⁻² Contained 93 7 1.3 × 10¹chemical 22 Liquid 6.4 × 10⁰ 1 99 1.0 × 10⁻² 92 8 1.2 × 10¹ chemical 23Liquid 1.1 × 10⁵ 3 97 3.l × 10⁻² Contained 95 5 1.9 × 10¹ chemical 24Liquid 6.7 × 10³ 3 97 3.1 × 10⁻² Contained 95 5 1.9 × 10¹ chemical 25

Table 2 was shown by dividing the table into Table 2 (part 1) and Table2 (part 2). The measurement results and the like of the respectiveliquid chemicals are described over the corresponding row of the abovetwo tables. For example, regarding the liquid chemical 1, the followingare shown in the tables: cyclohexanone was used as an organic solvent; acontent of Fe nanoparticles was 1.2×10⁵ particles/cm³, a content of Pbnanoparticles was 9.0×10² particles/cm³, a content of Cr nanoparticleswas 1.5×10³ particles/cm³, and a content of Ti nanoparticles was 3.0×10³particles/cm³; and Fe/Pb was 1.3×10², Fe/Cr was 8.0×10¹, and Fe/Ti was4.0×10¹. In addition, as a classification of Fe nanoparticles, a contentof particles A was 3% (on a number basis) with respect to a total numberof Fe nanoparticles, a total content of particles B and particles C was97% (on a number basis), and A/(B+C) was 3.1×10⁻². Furthermore, theliquid chemical 1 includes a high-boiling point organic compound, and asa classification of Fe nanoparticles, a content of particles U was 95%(on a number basis) with respect to a total number of Fe nanoparticles,a content of particles V was 5% (on a number basis), and U/V was1.9×10¹.

The other liquid chemicals are also described in the tables in the samemanner as in the liquid chemical 1.

Example 1

Defect inhibitive performance was evaluated using the above-preparedliquid chemical 1 as a pre-wetting solution. A resist composition 1 usedis as follows.

Resist Composition 1

A resist composition 1 was obtained by mixing each component at thefollowing composition.

-   -   Resin (A-1): 0.77 g    -   Acid-generating agent (B-1): 0.03 g    -   Basic compound (E-3): 0.03 g    -   PGMEA: 67.5 g    -   EL: 75g

Resin (A) and the Like Synthesis Example 1) Synthesis of Resin (A-1)

600 g of cyclohexanone was put in a 2 L flask, and an atmosphere wasreplaced with nitrogen at a flow rate of 100 mL/min over 1 hour.Thereafter, 4.60 g (0.02 mol) of a polymerization initiator, V-601(manufactured by Wako Pure Chemical Industries, Ltd.) was added, and atemperature was raised until an internal temperature reached 80° C.Next, the following monomer and 4.60 g (0.02 mol) of a polymerizationinitiator, V-601 (manufactured by Wako Pure Chemical Industries, Ltd.)were dissolved in 200 g of cyclohexanone to prepare a monomer solution.The monomer solution was added dropwise over 6 hours into the flaskheated to 80° C. After completion of the dropwise addition, a reactionwas further performed at 80° C. for 2 hours.

4-Acetoxystyrene 48.66 g (0.3 mol) 1-Ethylcyclopentyl methacrylate 109.4g (0.6 mol) Monomer 1  22.2 g (0.1 mol)

The reaction solution was cooled to room temperature and added dropwiseinto 3 L of hexane to precipitate a polymer. The filtered solid wasdissolved in 500 mL of acetone and added dropwise again into 3 L ofhexane. The filtered solid was dried under reduced pressure, and thereby160 g of a copolymer (A-1) of 4-acetoxystyrene/1-ethylcyclopentylmethacrylate/monomer 1 was obtained.

10 g of the polymer obtained above, 40 mL of methanol, 200 mL of1-methoxy-2-propanol, and 1.5 mL of concentrated hydrochloric acid wereadded to a reaction container. The mixture was heated to 80° C. andstirred for 5 hours. The reaction solution was air-cooled to roomtemperature and added dropwise into 3 L of distilled water. The filteredsolid was dissolved in 200 mL of acetone and added dropwise again into 3L of distilled water. The filtered solid was dried under reducedpressure, and thereby a resin (A-1) (8.5 g) was obtained. Aweight-average molecular weight (Mw) in terms of standard polystyrene bygel permeation chromatography (GPC) (solvent: THF (tetrahydrofuran)) was11,200, and a molecular weight dispersity (Mw/Mn) was 1.45. Acomposition and the like are shown in Table 3.

TABLE 4 Compositional ratio Table 3 Structure (molar ratio) from theleft Mw Mw/Mn Resin A-1

30/60/10 11,200 1.45

Photo-Acid Generator (B)

The following was used as a photo-acid generator.

Basic Compound (E)

The following was used as a basic compound.

Residue Defect Inhibitive Performance, Bridge Defect InhibitivePerformance, and Spot-Like Defect Inhibitive Performance

Residue defect inhibitive performance, bridge defect inhibitiveperformance, and spot-like defect inhibitive performance of the liquidchemicals were evaluated by the following method. In the test, a coaterdeveloper, “RF³⁵” manufactured by SOKUDO was used.

First, AL412 (manufactured by Brewer Science) was applied on a siliconwafer and baked at 200° C. for 60 seconds to form a resist underlayerfilm having a thickness of 20 nm. The pre-wetting solution (the liquidchemicals 1 to 17 and the liquid chemicals 19 and 20) was appliedthereon, and the resist composition was applied thereon and baked(Prebake: PB) at 100° C. for 60 seconds to form a resist film having athickness of 30 nm.

This resist film was exposed through a reflective type mask having apitch of 20 nm and a pattern width of 15 nm using an EUV exposuremachine (manufactured by ASML; NXE3350, NA: 0.33, Dipole: 90°, sigmaouter: 0.87, sigma inner: 0.35). Thereafter, heating was performed at85° C. for 60 seconds (Post Exposure Bake: PEB). Next, the film wasdeveloped by an organic solvent-based developer for 30 seconds andrinsed for 20 seconds. Subsequently, by rotating the wafer at a rotationspeed of 2000 rpm for 40 seconds, a line-and-space pattern having apitch of 20 nm and a pattern width of 15 nm was formed.

An image of the above pattern was obtained, and the obtained image wasanalyzed. The number of residues in an unexposed part per unit area wasobtained and evaluated according to the following standard (the resultsare shown in the column of “Residue defect inhibitive performance” inTable 4). In addition, the number of bridge-like defects betweenpatterns was obtained and evaluated according to the following standard.This is referred to as the number of bridge defects, and the results areshown in the column of “Bridge defect inhibitive performance” in Table4. Furthermore, EDX (energy dispersive X-ray analysis) was performed oncoordinates at which defects were detected, and as a result, defects inwhich metal atoms were not detected were defined as spot-like defects,and these were measured. The results were evaluated according to thefollowing standard and are shown in Table 4 in the column of “Spot-likedefect inhibitive performance.” In the following evaluation standard,“the number of defects” indicates each of the number of residue defectsand the number of bridge defects.

AA: The number of defects was less than 30.

A: The number of defects was 30 or more and less than 60.

B: The number of defects was 60 or more and less than 90.

C: The number of defects was 90 or more and less than 120.

D: The number of defects was 120 or more and less than 150.

E: The number of defects was 150 or more and less than 180.

F: The number of defects was 180 or more.

Pattern Width Uniform Performance

An image of the above pattern was obtained. The obtained image wasanalyzed to obtain Line Width Roughness (LWR). That is, in a case ofobserving patterns from the top, a distance from the center to an edgeof a pattern was observed at an arbitrary point, and measurementvariation was evaluated by 3σ. The results were evaluated according tothe following standard to evaluate pattern width uniform performance.The results are shown in Table 4.

AA: 3σ was less than 1.5 nm.

A: 3σ was 1.5 nm or more and less than 1.8 nm.

B: 3σ was 1.8 nm or more and less than 2.2 nm.

C: 3σ was 2.2 nm or more and less than 2.5 nm.

D: 3σ was 2.5 nm or more and less than 2.8 nm.

E: 3σ was 2.8 nm or more and less than 3.1 nm.

F: 3σ was 3.1 nm or more.

Examples 2 to 16 and Examples 18 to 23

Residue defect inhibitive performance, bridge defect inhibitiveperformance, spot-like defect inhibitive performance, and pattern widthuniform performance of each of liquid chemicals were evaluated in thesame manner as above except that liquid chemicals 2 to 16 and liquidchemicals 18 to 23 were used instead of the liquid chemical 1. Theresults are shown in Table 4.

Comparative Examples 1 and 2

Residue defect inhibitive performance, bridge defect inhibitiveperformance, spot-like defect inhibitive performance, and pattern widthuniform performance were evaluated in the same manner as above exceptthat liquid chemicals 24 and 25 were used instead of the liquidchemical 1. The results are shown in Table 4.

Example 17

Residue defect inhibitive performance, bridge defect inhibitiveperformance, spot-like defect inhibitive performance, and pattern widthuniform performance of a liquid chemical 17 were evaluated in the samemanner as above except that the pre-wetting solution was not used, andthe liquid chemical 17 was used as a developer. The results are shown inTable 4.

TABLE 4 Residue Bridge pattern Spot-like defect defect width defectLiquid inhibitive inhibitive uniform inhibitive chemical perfor- perfor-perfor- perfor- used rmance mance mance rmance Example 1 Liquid AA AA AAAA chemical 1 Example 2 Liquid AA A AA AA chemical 2 Example 3 Liquid AA A A chemical 3 Example 4 Liquid B B B B chemical 4 Example 5 Liquid BC B B chemical 5 Example 6 Liquid AA A A AA chemical 6 Example 7 LiquidA B A A chemical 7 Example 8 Liquid B c B B chemical 8 Example 9 LiquidAA A A AA chemical 9 Example 10 Liquid A B A A chemical 10 Example 11Liquid D c c c chemical 11 Example 12 Liquid B C B B chemical 12 Example13 Liquid AA A A A chemical 13 Example 14 Liquid C C D C chemical 14Example 15 Liquid D D E D chemical 15 Example 16 Liquid AA A AA AAchemical 16 Example 17 Liquid AA AA AA AA chemical 17 Example 18 LiquidAA AA AA AA chemical 18 Example 19 Liquid AA AA AA AA chemical 19Example 20 Liquid AA AA AA AA chemical 20 Example 21 Liquid AA AA AA AAchemical 21 Example 22 Liquid AA AA AA AA chemical 22 Example 23 LiquidAA AA AA AA chemical 23 Comparative Liquid F F E E Example 1 chemical 24Comparative Liquid E E F F Example 2 chemical 25

Example 24

A resist composition 2 that is a liquid chemical was obtained using thesame method and components as in the resist composition 1 except thatPGMEA: 67.5 g and EL: 75 g which were purified by the purificationmethod for the liquid chemical 1 described in Example 1 were usedinstead of PGMEA: 67.5 g and EL: 75 g in the resist composition 1.

Next, regarding the resist composition 2, the number of particlescontained which have a particle size of 0.5 to 17 nm in the liquidchemical was evaluated by the same method as described above, and thenumber thereof was the same as that of Example 1.

In addition, a pattern was formed by the same method as in Example 1except that the resist composition 2 was used, and the pre-wettingsolution was not used. In a case where residue defect inhibitiveperformance, bridge defect inhibitive performance, pattern width uniformperformance, and spot-like defect inhibitive performance were examined,the results were the same as those in Example 1.

The results in Table 4 show that the liquid chemicals of Examples 1 to16 and Examples 18 to 23 exhibited excellent residue defect inhibitiveperformance, excellent bridge defect inhibitive performance, excellentpattern width uniform performance, and excellent spot-like defectinhibitive performance in the case where the liquid chemicals were usedas the pre-wetting solutions.

In addition, the results in Table 4 show that the liquid chemical ofExample 17 exhibited excellent residue defect inhibitive performance,excellent bridge defect inhibitive performance, excellent pattern widthuniform performance, and excellent spot-like defect inhibitiveperformance in the case where the liquid chemical was used as thedeveloper.

Furthermore, the liquid chemical of Example 29 exhibited excellentresidue defect inhibitive performance, excellent bridge defectinhibitive performance, excellent pattern width uniform performance, andexcellent spot-like defect inhibitive performance as the resistsolution.

Furthermore, the liquid chemical 1 in which Fe/Cr was 1.0 or moreexhibited more excellent bridge defect inhibitive performance, moreexcellent pattern width uniform performance, and more excellentspot-like defect inhibitive performance, as compared to those of theliquid chemical 7.

Furthermore, the liquid chemical 1 in which F/C was 1.0×10⁴ or lessexhibited more excellent bridge defect inhibitive performance, moreexcellent pattern width uniform performance, and more excellentspot-like defect inhibitive performance, as compared to those of theliquid chemical 5.

In addition, the liquid chemical 1, in which a ratio of the number ofthe particles A contained to a total of the number of the particles Bcontained and the number of the particles C contained based on thenumber of the particles per unit volume of the liquid chemical was lessthan 1.0, exhibited more excellent bridge defect inhibitive performance,more excellent pattern width uniform performance, and more excellentspot-like defect inhibitive performance, as compared to those of theliquid chemical 11.

Furthermore, the liquid chemical 1 in which A/(B+C) was 1.0×10⁻¹ or lessexhibited more excellent bridge defect inhibitive performance, moreexcellent pattern width uniform performance, and more excellentspot-like defect inhibitive performance, as compared to those of theliquid chemical 12.

Furthermore, the liquid chemical 1 in which UN was 1.0×10¹ or moreexhibited more excellent bridge defect inhibitive performance, moreexcellent pattern width uniform performance, and more excellentspot-like defect inhibitive performance, as compared to those of theliquid chemical 15.

EXPLANATION OF REFERENCES

-   10: purification device-   11: production tank-   12(a), 12(b): filter unit-   13: filling device-   14: pipe line-   15(a): adjustment valve-   16: filtration device

What is claimed is:
 1. A liquid chemical comprising: an organic solvent;Fe nanoparticles containing a Fe atom and having a particle size of 0.5to 17 nm; and Pb nanoparticles containing a Pb atom and having aparticle size of 0.5 to 17 nm, wherein a ratio of the number of the Fenanoparticles contained to the number of the Pb nanoparticles containedis 1.0 to 1.0×10⁴, based on the number of the particles per unit volumeof the liquid chemical.
 2. The liquid chemical according to claim 1,further comprising: Cr nanoparticles containing a Cr atom and having aparticle size of 0.5 to 17 nm, wherein a ratio of the number of the Fenanoparticles contained to the number of the Cr nanoparticles containedis 1.0 to 1.0×10⁴, based on the number of the particles per unit volumeof the liquid chemical.
 3. The liquid chemical according to claim 1,further comprising: Ti nanoparticles containing a Ti atom and having aparticle size of 0.5 to 17 nm, wherein a ratio of the number of the Fenanoparticles contained to the number of the Ti nanoparticles containedis 1.0 to 1.0×10³, based on the number of the particles per unit volumeof the liquid chemical.
 4. The liquid chemical according to claim 1,which is for manufacturing a semiconductor device.
 5. The liquidchemical according to claim 1, wherein the Fe nanoparticles consist ofat least one selected from the group consisting of particles Aconsisting of a simple substance of Fe, particles B consisting of anoxide of a Fe atom, and particles C consisting of a simple substance ofFe and an oxide of a Fe atom.
 6. The liquid chemical according to claim5, wherein a ratio of the number of the particles A contained to a totalof the number of the particles B contained and the number of theparticles C contained is less than 1.0, based on the number of theparticles per unit volume of the liquid chemical.
 7. The liquid chemicalaccording to claim 6, wherein the ratio of the number of the particlescontained is 1.0×10⁻¹ or less.
 8. The liquid chemical according to claim1, further comprising: an organic compound having a boiling point of300° C. or higher.
 9. The liquid chemical according to claim 8, whereinat least some of the Fe nanoparticles are particles U containing theorganic compound.
 10. The liquid chemical according to claim 8, whereinat least some of the Fe nanoparticles are the particles U containing theorganic compound and particles V not containing the organic compound,and a ratio of the number of the particles U contained to the number ofthe particles V contained is 1.0×10¹ or more, based on the number of theparticles per unit volume of the liquid chemical.
 11. A method forproducing a liquid chemical, which is for producing the liquid chemicalaccording to claim 1, the method comprising: a filtration step offiltering a purification target substance containing an organic solventusing a filter to obtain the liquid chemical.
 12. The method forproducing a liquid chemical according to claim 11, wherein thefiltration step is a multi-stage filtration step in which thepurification target substance is passed through two or more kinds offilters different in at least one selected from the group consisting ofa filter material, a pore diameter, and a pore structure.
 13. The methodfor producing a liquid chemical according to claim 11, wherein, for thefilter, in a case of using one filter, a pore diameter of the filter is5 nm or smaller, and in a case of using two or more filters, a porediameter of a filter having a smallest pore diameter among the filtersis 5 nm or smaller.
 14. The liquid chemical according to claim 2,further comprising: Ti nanoparticles containing a Ti atom and having aparticle size of 0.5 to 17 nm, wherein a ratio of the number of the Fenanoparticles contained to the number of the Ti nanoparticles containedis 1.0 to 1.0×10³, based on the number of the particles per unit volumeof the liquid chemical.
 15. The liquid chemical according to claim 2,which is for manufacturing a semiconductor device.
 16. The liquidchemical according to claim 2, wherein the Fe nanoparticles consist ofat least one selected from the group consisting of particles Aconsisting of a simple substance of Fe, particles B consisting of anoxide of a Fe atom, and particles C consisting of a simple substance ofFe and an oxide of a Fe atom.
 17. The liquid chemical according to claim16, wherein a ratio of the number of the particles A contained to atotal of the number of the particles B contained and the number of theparticles C contained is less than 1.0, based on the number of theparticles per unit volume of the liquid chemical.
 18. The liquidchemical according to claim 17, wherein the ratio of the number of theparticles contained is 1.0×10⁻¹ or less.
 19. The liquid chemicalaccording to claim 2, further comprising: an organic compound having aboiling point of 300° C. or higher.
 20. A method for producing a liquidchemical, which is for producing the liquid chemical according to claim2, the method comprising: a filtration step of filtering a purificationtarget substance containing an organic solvent using a filter to obtainthe liquid chemical.